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Which of the following is not an example of associated colloids?- a)Sodium stearate
- b)Potassium stearate
- c)Gum
- d)Detergents
Correct answer is option 'C'. Can you explain this answer?
Which of the following is not an example of associated colloids?
a)
Sodium stearate
b)
Potassium stearate
c)
Gum
d)
Detergents
|
Pinky Kumari answered |
Because gum milk blood etc are examples of colloids they have homogeneous looking and heterogeneous mixtures.
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What is the common name of O2SCl2?- a)Sulfur oxochloride
- b)Sulfuryl dioxo-dichloride
- c)Sulfuryl chloride
- d)Thionyl chloride
Correct answer is option 'C'. Can you explain this answer?
What is the common name of O2SCl2?
a)
Sulfur oxochloride
b)
Sulfuryl dioxo-dichloride
c)
Sulfuryl chloride
d)
Thionyl chloride
|
Rutuja Mehta answered |
Common Name of O2SCl2
Sulfuryl Chloride
Explanation:
Sulfuryl chloride is a chemical compound with the formula SO2Cl2. It is a colorless to yellowish-red liquid that can react violently with water to release hydrogen chloride gas. Sulfuryl chloride is used as a reagent in organic synthesis, as a chlorinating agent for rubber and textiles, and as a fumigant in the food industry.
Sulfuryl chloride is the common name for O2SCl2 because it is derived from the combination of sulfur dioxide (SO2) and chlorine (Cl2) gases. The prefix "sulfonyl" is used to denote a functional group consisting of a sulfur atom doubly bonded to an oxygen atom and singly bonded to two other groups, usually carbon or hydrogen. In the case of sulfuryl chloride, the functional group is SO2Cl, which contains two oxygen atoms and two chlorine atoms. Therefore, the name "sulfuryl chloride" accurately describes the composition of the compound.
Sulfuryl Chloride
Explanation:
Sulfuryl chloride is a chemical compound with the formula SO2Cl2. It is a colorless to yellowish-red liquid that can react violently with water to release hydrogen chloride gas. Sulfuryl chloride is used as a reagent in organic synthesis, as a chlorinating agent for rubber and textiles, and as a fumigant in the food industry.
Sulfuryl chloride is the common name for O2SCl2 because it is derived from the combination of sulfur dioxide (SO2) and chlorine (Cl2) gases. The prefix "sulfonyl" is used to denote a functional group consisting of a sulfur atom doubly bonded to an oxygen atom and singly bonded to two other groups, usually carbon or hydrogen. In the case of sulfuryl chloride, the functional group is SO2Cl, which contains two oxygen atoms and two chlorine atoms. Therefore, the name "sulfuryl chloride" accurately describes the composition of the compound.
What is the process called when the molecules of a substance are retained at the surface of a solid or a liquid?- a)Absorption
- b)Adsorption
- c)Sorption
- d)Desorption
Correct answer is option 'B'. Can you explain this answer?
What is the process called when the molecules of a substance are retained at the surface of a solid or a liquid?
a)
Absorption
b)
Adsorption
c)
Sorption
d)
Desorption
|
Ashwini Shah answered |
Adsorption
Adsorption is a process in which the molecules of a substance are retained at the surface of a solid or a liquid. The substance that is adsorbed is called the adsorbate, and the surface on which it is adsorbed is called the adsorbent.
Types of Adsorption
Adsorption can be classified into two types:
1. Physical Adsorption or Physisorption: This type of adsorption involves weak van der Waals forces between the adsorbate and the adsorbent. The adsorbate molecules are only loosely attached to the surface of the adsorbent, and can be easily removed by changing the conditions like temperature, pressure, or concentration.
2. Chemical Adsorption or Chemisorption: This type of adsorption involves strong chemical bonds between the adsorbate and the adsorbent. The adsorbate molecules are chemically bonded to the surface of the adsorbent, and can only be removed by breaking the chemical bonds.
Factors Affecting Adsorption
The factors that affect adsorption include:
1. Nature of the Adsorbate: The adsorption depends on the nature of the adsorbate. Polar molecules are more strongly adsorbed than non-polar molecules.
2. Nature of the Adsorbent: The adsorption also depends on the nature of the adsorbent. Some materials like activated carbon, silica gel, and zeolites are good adsorbents.
3. Temperature: The adsorption increases with a decrease in temperature for physical adsorption, whereas it decreases with a decrease in temperature for chemisorption.
4. Pressure: The adsorption increases with an increase in pressure for physical adsorption, whereas it remains constant for chemisorption.
Uses of Adsorption
Adsorption has various uses, including:
1. Purification of water and air
2. Separation of gases
3. Catalysis
4. Adsorbent for chromatography
5. Adsorbent for gas masks
Conclusion
In conclusion, adsorption is a process in which the molecules of a substance are retained at the surface of a solid or a liquid. It can be classified into two types: physical adsorption and chemical adsorption. The factors that affect adsorption include the nature of the adsorbate, the nature of the adsorbent, temperature, and pressure. Adsorption has various uses, including purification of water and air, separation of gases, catalysis, and adsorbent for gas masks.
Adsorption is a process in which the molecules of a substance are retained at the surface of a solid or a liquid. The substance that is adsorbed is called the adsorbate, and the surface on which it is adsorbed is called the adsorbent.
Types of Adsorption
Adsorption can be classified into two types:
1. Physical Adsorption or Physisorption: This type of adsorption involves weak van der Waals forces between the adsorbate and the adsorbent. The adsorbate molecules are only loosely attached to the surface of the adsorbent, and can be easily removed by changing the conditions like temperature, pressure, or concentration.
2. Chemical Adsorption or Chemisorption: This type of adsorption involves strong chemical bonds between the adsorbate and the adsorbent. The adsorbate molecules are chemically bonded to the surface of the adsorbent, and can only be removed by breaking the chemical bonds.
Factors Affecting Adsorption
The factors that affect adsorption include:
1. Nature of the Adsorbate: The adsorption depends on the nature of the adsorbate. Polar molecules are more strongly adsorbed than non-polar molecules.
2. Nature of the Adsorbent: The adsorption also depends on the nature of the adsorbent. Some materials like activated carbon, silica gel, and zeolites are good adsorbents.
3. Temperature: The adsorption increases with a decrease in temperature for physical adsorption, whereas it decreases with a decrease in temperature for chemisorption.
4. Pressure: The adsorption increases with an increase in pressure for physical adsorption, whereas it remains constant for chemisorption.
Uses of Adsorption
Adsorption has various uses, including:
1. Purification of water and air
2. Separation of gases
3. Catalysis
4. Adsorbent for chromatography
5. Adsorbent for gas masks
Conclusion
In conclusion, adsorption is a process in which the molecules of a substance are retained at the surface of a solid or a liquid. It can be classified into two types: physical adsorption and chemical adsorption. The factors that affect adsorption include the nature of the adsorbate, the nature of the adsorbent, temperature, and pressure. Adsorption has various uses, including purification of water and air, separation of gases, catalysis, and adsorbent for gas masks.
Which of the following statements regarding emulsions is false?- a)Emulsions cannot be separated into their constituent liquids
- b)Emulsions show Brownian motion
- c)Emulsions show Tyndall effect
- d)Emulsions exhibit properties like Electrophoresis and Coagulation
Correct answer is option 'A'. Can you explain this answer?
Which of the following statements regarding emulsions is false?
a)
Emulsions cannot be separated into their constituent liquids
b)
Emulsions show Brownian motion
c)
Emulsions show Tyndall effect
d)
Emulsions exhibit properties like Electrophoresis and Coagulation
|
Avantika Dasgupta answered |
Emulsions are a type of colloidal dispersion in which two immiscible liquids, typically oil and water, are mixed together to form a stable mixture. The emulsion is composed of small droplets of one liquid dispersed throughout the other liquid. Emulsions have a wide range of applications, such as in food, cosmetics, and pharmaceuticals.
The statement that is false regarding emulsions is:
a) Emulsions cannot be separated into their constituent liquids.
Explanation:
Emulsions can indeed be separated into their constituent liquids through various methods. Some common separation techniques include:
1. Gravity separation: Emulsions can be left undisturbed for a period of time, allowing the lighter liquid to rise to the top and the heavier liquid to settle at the bottom. This process is known as creaming or sedimentation, and it can be used to separate the two liquids.
2. Centrifugation: By subjecting the emulsion to high-speed rotation in a centrifuge, the centrifugal force separates the two liquids based on their densities. The heavier liquid is forced to the bottom, while the lighter liquid is collected at the top.
3. Heating and cooling: Emulsions can sometimes undergo phase separation when heated or cooled. For example, if an oil-in-water emulsion is heated, the oil droplets may coalesce and rise to the top, allowing for separation.
4. Chemical methods: Various chemicals can be added to emulsions to break them down and separate the liquids. For instance, adding a salt solution can cause the emulsion to destabilize and separate into its constituent liquids.
It is important to note that while emulsions can be separated into their constituent liquids, the process may not always be easy or efficient. Factors such as the stability of the emulsion, the size of the droplets, and the properties of the liquids can all affect the separation process.
In conclusion, the statement that emulsions cannot be separated into their constituent liquids is false. Emulsions can be separated using different methods, such as gravity separation, centrifugation, heating and cooling, and chemical methods.
The statement that is false regarding emulsions is:
a) Emulsions cannot be separated into their constituent liquids.
Explanation:
Emulsions can indeed be separated into their constituent liquids through various methods. Some common separation techniques include:
1. Gravity separation: Emulsions can be left undisturbed for a period of time, allowing the lighter liquid to rise to the top and the heavier liquid to settle at the bottom. This process is known as creaming or sedimentation, and it can be used to separate the two liquids.
2. Centrifugation: By subjecting the emulsion to high-speed rotation in a centrifuge, the centrifugal force separates the two liquids based on their densities. The heavier liquid is forced to the bottom, while the lighter liquid is collected at the top.
3. Heating and cooling: Emulsions can sometimes undergo phase separation when heated or cooled. For example, if an oil-in-water emulsion is heated, the oil droplets may coalesce and rise to the top, allowing for separation.
4. Chemical methods: Various chemicals can be added to emulsions to break them down and separate the liquids. For instance, adding a salt solution can cause the emulsion to destabilize and separate into its constituent liquids.
It is important to note that while emulsions can be separated into their constituent liquids, the process may not always be easy or efficient. Factors such as the stability of the emulsion, the size of the droplets, and the properties of the liquids can all affect the separation process.
In conclusion, the statement that emulsions cannot be separated into their constituent liquids is false. Emulsions can be separated using different methods, such as gravity separation, centrifugation, heating and cooling, and chemical methods.
Which of the following is incorrect regarding receptors?- a)They have constant shape
- b)They are proteins
- c)The shape of receptors binding site changes to fit the messenger
- d)They are present in the cell membrane
Correct answer is option 'A'. Can you explain this answer?
Which of the following is incorrect regarding receptors?
a)
They have constant shape
b)
They are proteins
c)
The shape of receptors binding site changes to fit the messenger
d)
They are present in the cell membrane
|
Mihir Yadav answered |
Receptors
Receptors are specialized proteins that are present on the surface of cells or inside the cells. They play a key role in cellular communication and signal transduction.
Shape of Receptor Binding Site
The binding site of the receptor is the specific location where the messenger molecule or ligand binds to the receptor. The shape of the receptor binding site is not constant, but rather it changes to fit the shape of the messenger molecule. This allows the receptor to selectively bind to specific messenger molecules.
Presence of Receptors
Receptors are present in the cell membrane and also inside the cells. The receptors present in the cell membrane are called cell surface receptors, and they are involved in receiving signals from the extracellular environment. The receptors present inside the cells are called intracellular receptors, and they are involved in receiving signals from within the cell.
Protein Nature of Receptors
Receptors are proteins that are made up of amino acids. The amino acid sequence determines the overall shape of the receptor, including the shape of the binding site.
Incorrect Option
Option A, which states that receptors have a constant shape, is incorrect. The shape of the receptor binding site changes to fit the shape of the messenger molecule, allowing for selective binding.
Receptors are specialized proteins that are present on the surface of cells or inside the cells. They play a key role in cellular communication and signal transduction.
Shape of Receptor Binding Site
The binding site of the receptor is the specific location where the messenger molecule or ligand binds to the receptor. The shape of the receptor binding site is not constant, but rather it changes to fit the shape of the messenger molecule. This allows the receptor to selectively bind to specific messenger molecules.
Presence of Receptors
Receptors are present in the cell membrane and also inside the cells. The receptors present in the cell membrane are called cell surface receptors, and they are involved in receiving signals from the extracellular environment. The receptors present inside the cells are called intracellular receptors, and they are involved in receiving signals from within the cell.
Protein Nature of Receptors
Receptors are proteins that are made up of amino acids. The amino acid sequence determines the overall shape of the receptor, including the shape of the binding site.
Incorrect Option
Option A, which states that receptors have a constant shape, is incorrect. The shape of the receptor binding site changes to fit the shape of the messenger molecule, allowing for selective binding.
5 moles of liquid X and 10 moles of liquid Y make a solution having a total vapour pressure 70 torr. The vapour pressures of pure X and pure Y are 64 torr and 76 torr respectively. Which of the following is true regarding the described solution?- a)The solution shows positive deviation
- b)The solution shows negative deviation
- c)The solution is ideal
- d)The solution has volume greater than the sum of individual volumes
Correct answer is option 'B'. Can you explain this answer?
5 moles of liquid X and 10 moles of liquid Y make a solution having a total vapour pressure 70 torr. The vapour pressures of pure X and pure Y are 64 torr and 76 torr respectively. Which of the following is true regarding the described solution?
a)
The solution shows positive deviation
b)
The solution shows negative deviation
c)
The solution is ideal
d)
The solution has volume greater than the sum of individual volumes
|
Shalini Basu answered |
Given information:
- 5 moles of liquid X and 10 moles of liquid Y make a solution.
- The total vapour pressure of the solution is 70 torr.
- The vapour pressures of pure X and Y are 64 torr and 76 torr respectively.
To determine if the solution shows positive or negative deviation from Raoult's law, we need to calculate the expected vapour pressure of the solution using Raoult's law and compare it with the actual vapour pressure.
Using Raoult's law, the expected vapour pressure of the solution can be calculated as follows:
P(total) = X(A) * P(A) + X(B) * P(B)
Where,
P(total) = Total vapour pressure of the solution
X(A) = Mole fraction of component A (liquid X)
X(B) = Mole fraction of component B (liquid Y)
P(A) = Vapour pressure of pure component A (liquid X)
P(B) = Vapour pressure of pure component B (liquid Y)
Plugging in the values, we get:
P(total) = (5/15) * 64 + (10/15) * 76
= 42.67 + 50.67
= 93.34 torr
However, the actual vapour pressure of the solution is given as 70 torr.
Since the expected vapour pressure is higher than the actual vapour pressure, the solution shows negative deviation from Raoult's law.
Explanation:
When a solution shows negative deviation from Raoult's law, it means that the actual vapour pressure of the solution is lower than the expected vapour pressure calculated using Raoult's law. This happens when the intermolecular forces between the components of the solution are stronger than the intermolecular forces between the components and the solvent.
In this case, the vapour pressure of the solution is lower than expected, which means that the intermolecular forces between the components (liquid X and Y) are stronger than the intermolecular forces between the components and the solvent. This causes the components to stick together more than they would in an ideal solution, resulting in a lower vapour pressure than expected. Therefore, option B is the correct answer.
- 5 moles of liquid X and 10 moles of liquid Y make a solution.
- The total vapour pressure of the solution is 70 torr.
- The vapour pressures of pure X and Y are 64 torr and 76 torr respectively.
To determine if the solution shows positive or negative deviation from Raoult's law, we need to calculate the expected vapour pressure of the solution using Raoult's law and compare it with the actual vapour pressure.
Using Raoult's law, the expected vapour pressure of the solution can be calculated as follows:
P(total) = X(A) * P(A) + X(B) * P(B)
Where,
P(total) = Total vapour pressure of the solution
X(A) = Mole fraction of component A (liquid X)
X(B) = Mole fraction of component B (liquid Y)
P(A) = Vapour pressure of pure component A (liquid X)
P(B) = Vapour pressure of pure component B (liquid Y)
Plugging in the values, we get:
P(total) = (5/15) * 64 + (10/15) * 76
= 42.67 + 50.67
= 93.34 torr
However, the actual vapour pressure of the solution is given as 70 torr.
Since the expected vapour pressure is higher than the actual vapour pressure, the solution shows negative deviation from Raoult's law.
Explanation:
When a solution shows negative deviation from Raoult's law, it means that the actual vapour pressure of the solution is lower than the expected vapour pressure calculated using Raoult's law. This happens when the intermolecular forces between the components of the solution are stronger than the intermolecular forces between the components and the solvent.
In this case, the vapour pressure of the solution is lower than expected, which means that the intermolecular forces between the components (liquid X and Y) are stronger than the intermolecular forces between the components and the solvent. This causes the components to stick together more than they would in an ideal solution, resulting in a lower vapour pressure than expected. Therefore, option B is the correct answer.
Which of the following aldehydes can produce 1o alcohols when treated with Grignard reagent?- a)Methanal
- b)Ethanal
- c)Propanal
- d)Butanal
Correct answer is option 'A'. Can you explain this answer?
Which of the following aldehydes can produce 1o alcohols when treated with Grignard reagent?
a)
Methanal
b)
Ethanal
c)
Propanal
d)
Butanal
|
|
Maulik Dasgupta answered |
Aldehydes can be converted to primary alcohols by reacting them with Grignard reagents.
Grignard reagents are organometallic compounds that contain a carbon-metal bond, usually magnesium. They are highly reactive and can add to the carbonyl group of aldehydes and ketones to form alcohols.
In this case, we need to identify the aldehyde that can produce a primary alcohol when treated with a Grignard reagent.
Methanal or formaldehyde is the only aldehyde among the given options that can produce a primary alcohol when treated with a Grignard reagent.
When methanal reacts with a Grignard reagent, such as methylmagnesium bromide (CH3MgBr), the following reaction takes place:
CH2O + CH3MgBr → CH3CH2OH + MgBrOH
The product of this reaction is ethanol, which is a primary alcohol.
On the other hand, the other aldehydes, ethanal, propanal, and butanal, can only produce secondary alcohols when treated with Grignard reagents.
Therefore, the correct answer is option A, methanal.
Grignard reagents are organometallic compounds that contain a carbon-metal bond, usually magnesium. They are highly reactive and can add to the carbonyl group of aldehydes and ketones to form alcohols.
In this case, we need to identify the aldehyde that can produce a primary alcohol when treated with a Grignard reagent.
Methanal or formaldehyde is the only aldehyde among the given options that can produce a primary alcohol when treated with a Grignard reagent.
When methanal reacts with a Grignard reagent, such as methylmagnesium bromide (CH3MgBr), the following reaction takes place:
CH2O + CH3MgBr → CH3CH2OH + MgBrOH
The product of this reaction is ethanol, which is a primary alcohol.
On the other hand, the other aldehydes, ethanal, propanal, and butanal, can only produce secondary alcohols when treated with Grignard reagents.
Therefore, the correct answer is option A, methanal.
Which of the following is true regarding azeotropes?- a)An azeotrope does not exhibit the same concentration in the vapour phase and the liquid phase
- b)Azeotropic mixtures cannot be separated into their constituents by fractional distillation
- c)In case of minimum boiling azeotropes, the boiling point of the azeotrope is higher than the boiling point of either of the pure components
- d)In case of maximum boiling azeotropes, the boiling point of the azeotrope is lesser than the boiling point of either of the pure components
Correct answer is option 'D'. Can you explain this answer?
Which of the following is true regarding azeotropes?
a)
An azeotrope does not exhibit the same concentration in the vapour phase and the liquid phase
b)
Azeotropic mixtures cannot be separated into their constituents by fractional distillation
c)
In case of minimum boiling azeotropes, the boiling point of the azeotrope is higher than the boiling point of either of the pure components
d)
In case of maximum boiling azeotropes, the boiling point of the azeotrope is lesser than the boiling point of either of the pure components
|
Kanish Dhiman answered |
What is each point (position of particle) in a crystal lattice termed as?- a)Lattice index
- b)Lattice point
- c)Lattice lines
- d)Lattice spot
Correct answer is option 'A'. Can you explain this answer?
What is each point (position of particle) in a crystal lattice termed as?
a)
Lattice index
b)
Lattice point
c)
Lattice lines
d)
Lattice spot
|
|
Rutuja Ahuja answered |
The correct answer is option 'B' - Lattice point.
Explanation:
A crystal lattice is a three-dimensional arrangement of atoms, ions or molecules in a regular pattern. The points where the atoms, ions or molecules are located in the crystal lattice are called lattice points.
The lattice point is the smallest repeating unit of the crystal lattice, and it represents the position of the particle in the crystal. The lattice points are arranged in a regular pattern, and the pattern is repeated in all directions to form a crystal lattice.
Some key points to remember:
- The lattice points in a crystal lattice are also called lattice sites.
- The lattice points are represented by the coordinates of the particle in the crystal lattice.
- The lattice points are usually labeled using a set of three integers, representing the x, y, and z coordinates of the particle in the crystal lattice.
- The lattice points in a crystal lattice are important in determining the properties of the crystal, such as its symmetry and diffraction pattern.
Explanation:
A crystal lattice is a three-dimensional arrangement of atoms, ions or molecules in a regular pattern. The points where the atoms, ions or molecules are located in the crystal lattice are called lattice points.
The lattice point is the smallest repeating unit of the crystal lattice, and it represents the position of the particle in the crystal. The lattice points are arranged in a regular pattern, and the pattern is repeated in all directions to form a crystal lattice.
Some key points to remember:
- The lattice points in a crystal lattice are also called lattice sites.
- The lattice points are represented by the coordinates of the particle in the crystal lattice.
- The lattice points are usually labeled using a set of three integers, representing the x, y, and z coordinates of the particle in the crystal lattice.
- The lattice points in a crystal lattice are important in determining the properties of the crystal, such as its symmetry and diffraction pattern.
Which of the following is a bactericidal antibiotic?- a)Erythromycin
- b)Ofloxacin
- c)Tetracycline
- d)Chloramphenicol
Correct answer is option 'B'. Can you explain this answer?
Which of the following is a bactericidal antibiotic?
a)
Erythromycin
b)
Ofloxacin
c)
Tetracycline
d)
Chloramphenicol
|
|
Nandini Iyer answered |
Antibiotics can either kill the target microbes (cidal effect) or can prevent it from pathogenic action (static effect). The former are known as bactericidal and the latter is known as bacteriostatic.
What is the name of the process of extracting sulfur on commercial scale?- a)Bosch process
- b)Boyle process
- c)Ostwald process
- d)Frasch process
Correct answer is option 'D'. Can you explain this answer?
What is the name of the process of extracting sulfur on commercial scale?
a)
Bosch process
b)
Boyle process
c)
Ostwald process
d)
Frasch process
|
|
Jhanvi Sengupta answered |
The Frasch process is the name of the process of extracting sulfur on a commercial scale. This process was invented in 1891 by Herman Frasch, an American chemist who wanted to find a way to extract sulfur that would be more efficient than the existing methods.
How does the Frasch process work?
The Frasch process involves drilling a hole into a sulfur deposit and pumping superheated water into the deposit. The water melts the sulfur, which is then forced to the surface by compressed air. The sulfur is then collected and purified.
Advantages of the Frasch process
The Frasch process is a highly efficient way of extracting sulfur, and it has several advantages over other methods:
1. High purity: The sulfur extracted by the Frasch process is of very high purity, which makes it ideal for use in a variety of industrial applications.
2. Low environmental impact: The Frasch process is a relatively clean process that does not produce a lot of pollution or waste.
3. High yield: The Frasch process has a high yield, which means that it is able to extract a large amount of sulfur from a deposit.
4. Low cost: The Frasch process is a cost-effective way of extracting sulfur, which makes it a popular choice for commercial operations.
Conclusion
The Frasch process is a highly efficient and cost-effective way of extracting sulfur on a commercial scale. It has several advantages over other methods and has become the preferred method for many industrial applications that require high-purity sulfur.
How does the Frasch process work?
The Frasch process involves drilling a hole into a sulfur deposit and pumping superheated water into the deposit. The water melts the sulfur, which is then forced to the surface by compressed air. The sulfur is then collected and purified.
Advantages of the Frasch process
The Frasch process is a highly efficient way of extracting sulfur, and it has several advantages over other methods:
1. High purity: The sulfur extracted by the Frasch process is of very high purity, which makes it ideal for use in a variety of industrial applications.
2. Low environmental impact: The Frasch process is a relatively clean process that does not produce a lot of pollution or waste.
3. High yield: The Frasch process has a high yield, which means that it is able to extract a large amount of sulfur from a deposit.
4. Low cost: The Frasch process is a cost-effective way of extracting sulfur, which makes it a popular choice for commercial operations.
Conclusion
The Frasch process is a highly efficient and cost-effective way of extracting sulfur on a commercial scale. It has several advantages over other methods and has become the preferred method for many industrial applications that require high-purity sulfur.
Who first recognized sulfur as an element?- a)John Dalton
- b)Humphry Davy
- c)Louis Pasteur
- d)Antoine Lavoisier
Correct answer is option 'D'. Can you explain this answer?
Who first recognized sulfur as an element?
a)
John Dalton
b)
Humphry Davy
c)
Louis Pasteur
d)
Antoine Lavoisier
|
|
Shraddha Chavan answered |
Recognition of Sulfur as an Element
Introduction:
Sulfur is a chemical element with the symbol S and atomic number 16. It is a nonmetallic element and is found in abundance in nature. In the early days, sulfur was known to humans for its medicinal and industrial use, but its elemental nature was unknown.
Lavoisier's Contribution:
Antoine Lavoisier, a French chemist, is credited with recognizing sulfur as an element. In 1777, he conducted experiments on sulfur and its compounds and concluded that sulfur is an element. Lavoisier observed that when sulfur is burned in air, it combines with oxygen to form a new substance that has different properties than sulfur or oxygen. He called this substance sulfuric acid.
Other Contributions:
Although Lavoisier is credited with recognizing sulfur as an element, several other chemists also contributed to our understanding of sulfur. Some of them are:
- Johann Becher: He proposed the phlogiston theory, which stated that sulfur was a compound of phlogiston and earth.
- Joseph Priestley: He discovered oxygen and showed that it could combine with sulfur to form sulfur dioxide.
- Carl Wilhelm Scheele: He discovered several chemical elements, including oxygen, chlorine, and manganese. He also discovered sulfur dioxide and showed that it could combine with water to form sulfuric acid.
Conclusion:
In conclusion, Antoine Lavoisier recognized sulfur as an element through his experiments on sulfur and its compounds. However, several other chemists also contributed to our understanding of sulfur and its properties.
Introduction:
Sulfur is a chemical element with the symbol S and atomic number 16. It is a nonmetallic element and is found in abundance in nature. In the early days, sulfur was known to humans for its medicinal and industrial use, but its elemental nature was unknown.
Lavoisier's Contribution:
Antoine Lavoisier, a French chemist, is credited with recognizing sulfur as an element. In 1777, he conducted experiments on sulfur and its compounds and concluded that sulfur is an element. Lavoisier observed that when sulfur is burned in air, it combines with oxygen to form a new substance that has different properties than sulfur or oxygen. He called this substance sulfuric acid.
Other Contributions:
Although Lavoisier is credited with recognizing sulfur as an element, several other chemists also contributed to our understanding of sulfur. Some of them are:
- Johann Becher: He proposed the phlogiston theory, which stated that sulfur was a compound of phlogiston and earth.
- Joseph Priestley: He discovered oxygen and showed that it could combine with sulfur to form sulfur dioxide.
- Carl Wilhelm Scheele: He discovered several chemical elements, including oxygen, chlorine, and manganese. He also discovered sulfur dioxide and showed that it could combine with water to form sulfuric acid.
Conclusion:
In conclusion, Antoine Lavoisier recognized sulfur as an element through his experiments on sulfur and its compounds. However, several other chemists also contributed to our understanding of sulfur and its properties.
How does the solubility of gas change in a liquid, as described?- a)Decreases with increasing temperature
- b)Increases with increasing temperature
- c)Increases with decreasing pressure
- d)Decreases with increasing pressure
Correct answer is option 'A'. Can you explain this answer?
How does the solubility of gas change in a liquid, as described?
a)
Decreases with increasing temperature
b)
Increases with increasing temperature
c)
Increases with decreasing pressure
d)
Decreases with increasing pressure
|
Nisha Patel answered |
Solubility of gas in a liquid and its dependence on temperature and pressure is an important concept in chemistry. The solubility of gas in a liquid is determined by various factors such as temperature, pressure, nature of the gas, and the nature of the liquid. However, the most significant factor affecting the solubility of gas in a liquid is temperature.
Temperature and Solubility:
As the temperature of the liquid increases, the solubility of gas in the liquid decreases. This is because the gas molecules gain kinetic energy at higher temperatures and tend to move away from each other, making it easier for them to escape from the liquid. This phenomenon is known as gas evolution. Conversely, at lower temperatures, the kinetic energy of the gas molecules decreases, making it easier for them to dissolve in the liquid. Hence, the solubility of gas in a liquid decreases with increasing temperature.
Pressure and Solubility:
The solubility of gas in a liquid also depends on the pressure exerted on the gas. According to Henry's law, the solubility of a gas in a liquid is directly proportional to the pressure of the gas above the liquid. Therefore, the solubility of gas in a liquid increases with increasing pressure. When the pressure above a liquid-gas system is increased, the gas molecules are pushed into the liquid, and the solubility of the gas in the liquid increases. Conversely, when the pressure above a liquid-gas system is decreased, the gas molecules tend to escape from the liquid, and the solubility of the gas in the liquid decreases.
Conclusion:
In conclusion, the solubility of gas in a liquid is mainly influenced by temperature and pressure. The solubility of gas in a liquid decreases with increasing temperature and increases with increasing pressure. These factors play a crucial role in various chemical reactions and processes and are essential for understanding the behavior of gas-liquid systems.
Temperature and Solubility:
As the temperature of the liquid increases, the solubility of gas in the liquid decreases. This is because the gas molecules gain kinetic energy at higher temperatures and tend to move away from each other, making it easier for them to escape from the liquid. This phenomenon is known as gas evolution. Conversely, at lower temperatures, the kinetic energy of the gas molecules decreases, making it easier for them to dissolve in the liquid. Hence, the solubility of gas in a liquid decreases with increasing temperature.
Pressure and Solubility:
The solubility of gas in a liquid also depends on the pressure exerted on the gas. According to Henry's law, the solubility of a gas in a liquid is directly proportional to the pressure of the gas above the liquid. Therefore, the solubility of gas in a liquid increases with increasing pressure. When the pressure above a liquid-gas system is increased, the gas molecules are pushed into the liquid, and the solubility of the gas in the liquid increases. Conversely, when the pressure above a liquid-gas system is decreased, the gas molecules tend to escape from the liquid, and the solubility of the gas in the liquid decreases.
Conclusion:
In conclusion, the solubility of gas in a liquid is mainly influenced by temperature and pressure. The solubility of gas in a liquid decreases with increasing temperature and increases with increasing pressure. These factors play a crucial role in various chemical reactions and processes and are essential for understanding the behavior of gas-liquid systems.
Which of the following statements is true with respect to the extent of physisorption?- a)Increases with increase in temperature
- b)Decreases with increase in surface area
- c)Decreases with increase in the strength of Van der Waals forces
- d)Decreases with increase in temperature
Correct answer is option 'D'. Can you explain this answer?
Which of the following statements is true with respect to the extent of physisorption?
a)
Increases with increase in temperature
b)
Decreases with increase in surface area
c)
Decreases with increase in the strength of Van der Waals forces
d)
Decreases with increase in temperature
|
|
Swati Verma answered |
Physisorption is an exothermic process. According to Le-Chatelier’s principle, an exothermic reaction is favoured by a decrease in temperature. Therefore, the extent of physisorption decreases on increasing temperature.
Which of the following statements is true with respect to the types of adsorption?- a)Chemisorption is stronger than physisorption
- b)Physisorption is stronger than chemisorption
- c)They are both equal
- d)They cannot be compared
Correct answer is option 'A'. Can you explain this answer?
Which of the following statements is true with respect to the types of adsorption?
a)
Chemisorption is stronger than physisorption
b)
Physisorption is stronger than chemisorption
c)
They are both equal
d)
They cannot be compared
|
|
Shalini Choudhary answered |
Types of Adsorption
There are two types of adsorption: physisorption and chemisorption.
Physisorption
Physisorption, also known as physical adsorption, is the adsorption of molecules or atoms onto a surface through weak van der Waals forces. It occurs when the adsorbate molecule interacts with the surface through weak electrostatic forces. Physisorption is a reversible process and occurs at low temperatures.
Chemisorption
Chemisorption, also known as chemical adsorption, is the adsorption of molecules onto a surface through chemical bonds. It occurs when the adsorbate molecule interacts with the surface through strong chemical bonds. Chemisorption is an irreversible process and occurs at high temperatures.
Strength of Adsorption
The strength of adsorption can be compared based on the energy required to remove the adsorbed molecule from the surface. Chemisorption is stronger than physisorption because chemisorption involves the formation of chemical bonds between the adsorbate and the surface, which requires more energy to break than weak van der Waals forces.
Therefore, option 'A' is the correct answer: Chemisorption is stronger than physisorption.
There are two types of adsorption: physisorption and chemisorption.
Physisorption
Physisorption, also known as physical adsorption, is the adsorption of molecules or atoms onto a surface through weak van der Waals forces. It occurs when the adsorbate molecule interacts with the surface through weak electrostatic forces. Physisorption is a reversible process and occurs at low temperatures.
Chemisorption
Chemisorption, also known as chemical adsorption, is the adsorption of molecules onto a surface through chemical bonds. It occurs when the adsorbate molecule interacts with the surface through strong chemical bonds. Chemisorption is an irreversible process and occurs at high temperatures.
Strength of Adsorption
The strength of adsorption can be compared based on the energy required to remove the adsorbed molecule from the surface. Chemisorption is stronger than physisorption because chemisorption involves the formation of chemical bonds between the adsorbate and the surface, which requires more energy to break than weak van der Waals forces.
Therefore, option 'A' is the correct answer: Chemisorption is stronger than physisorption.
When a single substance can crystallize in two or more forms under different conditions provided, it is called as _________- a)Polymorphous
- b)Isomorphous
- c)Semimorphous
- d)Multimorphous
Correct answer is option 'A'. Can you explain this answer?
When a single substance can crystallize in two or more forms under different conditions provided, it is called as _________
a)
Polymorphous
b)
Isomorphous
c)
Semimorphous
d)
Multimorphous
|
Tanuja Kapoor answered |
Isomorphous is when two or more substances have the same crystal structure. Polymorphous is when a single substance can crystallize in two or more forms depending upon the conditions.
Which of the following is not an example of a non-ideal solution showing negative deviation?- a)HNO3 + Water
- b)HCl + Water
- c)Acetic acid + Pyridine
- d)Carbon tetrachloride + Toluene
Correct answer is option 'D'. Can you explain this answer?
Which of the following is not an example of a non-ideal solution showing negative deviation?
a)
HNO3 + Water
b)
HCl + Water
c)
Acetic acid + Pyridine
d)
Carbon tetrachloride + Toluene
|
|
Swati Verma answered |
HNO3 + Water, HCl + Water and Acetic acid + Pyridine are non-ideal solutions showing negative deviations. Carbon tetrachloride + Toluene is an example of non-ideal solution showing positive deviation.
What is the coordination number of a body-centered unit cell?- a)6
- b)12
- c)8
- d)4
Correct answer is option 'C'. Can you explain this answer?
What is the coordination number of a body-centered unit cell?
a)
6
b)
12
c)
8
d)
4
|
Pragati Choudhury answered |
Coordination Number of a Body-Centered Unit Cell
Body-centered unit cells are one of the three types of cubic unit cells in crystallography. In a body-centered cubic unit cell, atoms are present at the eight corners of the cube and one atom at the center of the cube. The coordination number is the number of nearest neighbors that an atom has in a crystal structure.
Explanation:
- In a body-centered unit cell, each atom at the corner is shared among eight adjacent unit cells.
- In addition, the atom at the center is only shared among the neighboring unit cell.
- Therefore, each atom in a body-centered unit cell has 8 nearest neighbors contributed by the corner atoms and 1 nearest neighbor contributed by the central atom.
Calculation:
- The coordination number for a body-centered unit cell is the sum of these nearest neighbors, which is 8 (from the corner atoms) + 1 (from the central atom) = 9.
- However, we only consider the immediate neighbors in the same unit cell, so the coordination number is 8 for a body-centered unit cell.
Therefore, the coordination number of a body-centered unit cell is 8.
Body-centered unit cells are one of the three types of cubic unit cells in crystallography. In a body-centered cubic unit cell, atoms are present at the eight corners of the cube and one atom at the center of the cube. The coordination number is the number of nearest neighbors that an atom has in a crystal structure.
Explanation:
- In a body-centered unit cell, each atom at the corner is shared among eight adjacent unit cells.
- In addition, the atom at the center is only shared among the neighboring unit cell.
- Therefore, each atom in a body-centered unit cell has 8 nearest neighbors contributed by the corner atoms and 1 nearest neighbor contributed by the central atom.
Calculation:
- The coordination number for a body-centered unit cell is the sum of these nearest neighbors, which is 8 (from the corner atoms) + 1 (from the central atom) = 9.
- However, we only consider the immediate neighbors in the same unit cell, so the coordination number is 8 for a body-centered unit cell.
Therefore, the coordination number of a body-centered unit cell is 8.
What is the criterion of the feasibility of a reaction at any temperature?- a)ΔG of the reaction must be positive
- b)ΔG of the reaction must be negative
- c)ΔG of the reaction must be equal to zero
- d)Does not depend on ΔG of the reaction
Correct answer is option 'B'. Can you explain this answer?
What is the criterion of the feasibility of a reaction at any temperature?
a)
ΔG of the reaction must be positive
b)
ΔG of the reaction must be negative
c)
ΔG of the reaction must be equal to zero
d)
Does not depend on ΔG of the reaction
|
Vivek Rana answered |
The criterion of the feasibility of a reaction at any temperature is that the ΔG of the reaction must be negative. For a reaction to be spontaneous, the value of the change in Gibbs energy of the reaction must always be negative.
When CO2 is introduced into aerated drinks and sealed, what is the nature of the graph between partial pressure of CO2 and its concentration in the drink?- a)Exponentially increasing
- b)Positive slope
- c)Negative slope
- d)Constant
Correct answer is option 'B'. Can you explain this answer?
When CO2 is introduced into aerated drinks and sealed, what is the nature of the graph between partial pressure of CO2 and its concentration in the drink?
a)
Exponentially increasing
b)
Positive slope
c)
Negative slope
d)
Constant
|
|
Rhea Iyer answered |
Nature of the graph between partial pressure of CO2 and its concentration in aerated drinks
Introduction
When CO2 is introduced into aerated drinks and sealed, it dissolves in the drink and establishes an equilibrium between the gas phase and the liquid phase. The concentration of CO2 in the drink depends on the partial pressure of CO2 in the gas phase, which in turn depends on the temperature and the amount of CO2 added.
Graph between partial pressure of CO2 and its concentration in aerated drinks
The graph between partial pressure of CO2 and its concentration in aerated drinks is a positive slope. This means that as the partial pressure of CO2 increases, the concentration of CO2 in the drink also increases. This relationship is governed by Henry's law, which states that the concentration of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid.
Explanation
The positive slope of the graph can be explained by the fact that when CO2 is added to the drink, it dissolves in the liquid until the partial pressure of CO2 in the gas phase is in equilibrium with the concentration of CO2 in the liquid. As the partial pressure of CO2 increases, more CO2 dissolves in the drink until the equilibrium is reached. Therefore, the concentration of CO2 in the drink increases with increasing partial pressure of CO2.
Conclusion
In conclusion, the nature of the graph between partial pressure of CO2 and its concentration in aerated drinks is a positive slope. This relationship is governed by Henry's law, which states that the concentration of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid.
Introduction
When CO2 is introduced into aerated drinks and sealed, it dissolves in the drink and establishes an equilibrium between the gas phase and the liquid phase. The concentration of CO2 in the drink depends on the partial pressure of CO2 in the gas phase, which in turn depends on the temperature and the amount of CO2 added.
Graph between partial pressure of CO2 and its concentration in aerated drinks
The graph between partial pressure of CO2 and its concentration in aerated drinks is a positive slope. This means that as the partial pressure of CO2 increases, the concentration of CO2 in the drink also increases. This relationship is governed by Henry's law, which states that the concentration of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid.
Explanation
The positive slope of the graph can be explained by the fact that when CO2 is added to the drink, it dissolves in the liquid until the partial pressure of CO2 in the gas phase is in equilibrium with the concentration of CO2 in the liquid. As the partial pressure of CO2 increases, more CO2 dissolves in the drink until the equilibrium is reached. Therefore, the concentration of CO2 in the drink increases with increasing partial pressure of CO2.
Conclusion
In conclusion, the nature of the graph between partial pressure of CO2 and its concentration in aerated drinks is a positive slope. This relationship is governed by Henry's law, which states that the concentration of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid.
Stainless steel is a/an ______ alloy.- a)vacant
- b)interstitial
- c)substitution
- d)pure
Correct answer is option 'B'. Can you explain this answer?
Stainless steel is a/an ______ alloy.
a)
vacant
b)
interstitial
c)
substitution
d)
pure
|
|
Swati Verma answered |
Stainless steel is an interstitial alloy. Carbon atoms are introduced into interstitial spaces of iron lattice as an impurity. Further alloying sees the introduction of nickel, chromium in the interstitial spaces.
Identify the most suitable reagent for the conversion of ethanal to acetic acid.- a)Alkaline KMnO4; H3O+
- b)Jones reagent
- c)Tollen’s reagent
- d)LiAlH4
Correct answer is option 'C'. Can you explain this answer?
Identify the most suitable reagent for the conversion of ethanal to acetic acid.
a)
Alkaline KMnO4; H3O+
b)
Jones reagent
c)
Tollen’s reagent
d)
LiAlH4
|
Nandini Nair answered |
Reagentd)PCC (pyridinium chlorochromate)
The most suitable reagent for the conversion of ethanal (also known as acetaldehyde) to acetic acid is PCC (pyridinium chlorochromate). PCC is commonly used for the oxidation of primary alcohols to aldehydes or carboxylic acids. In this case, PCC will oxidize ethanal to acetic acid.
Alkaline KMnO4 can also be used to oxidize ethanal to acetic acid, but it is a harsher reagent and can lead to over-oxidation.
Jones reagent is not suitable for this conversion as it is used for the oxidation of primary and secondary alcohols to carboxylic acids, but not for the oxidation of aldehydes.
Tollen's reagent (ammoniacal silver nitrate) is used for the oxidation of aldehydes to carboxylic acids, but it requires a specific reaction condition and is not commonly used for this conversion.
The most suitable reagent for the conversion of ethanal (also known as acetaldehyde) to acetic acid is PCC (pyridinium chlorochromate). PCC is commonly used for the oxidation of primary alcohols to aldehydes or carboxylic acids. In this case, PCC will oxidize ethanal to acetic acid.
Alkaline KMnO4 can also be used to oxidize ethanal to acetic acid, but it is a harsher reagent and can lead to over-oxidation.
Jones reagent is not suitable for this conversion as it is used for the oxidation of primary and secondary alcohols to carboxylic acids, but not for the oxidation of aldehydes.
Tollen's reagent (ammoniacal silver nitrate) is used for the oxidation of aldehydes to carboxylic acids, but it requires a specific reaction condition and is not commonly used for this conversion.
Which of the following arrangements of particles does a simple cubic lattice follow?- a)ABAB
- b)AABB
- c)ABCABC
- d)AAA
Correct answer is option 'D'. Can you explain this answer?
Which of the following arrangements of particles does a simple cubic lattice follow?
a)
ABAB
b)
AABB
c)
ABCABC
d)
AAA
|
|
Anu Sharma answered |
Simple Cubic Lattice Arrangement
A simple cubic lattice is a type of crystal structure where particles are arranged in a cubic pattern with one particle at each corner of the cube. The arrangement is known as a primitive cubic lattice.
Arrangement of Particles
The arrangement of particles in a simple cubic lattice follows the pattern of AAA. This means that all particles (atoms or ions) in the lattice are identical and have the same position in the crystal structure.
Explanation
In a simple cubic lattice, the particles are arranged in a cubic pattern with one particle at each corner of the cube. This arrangement is known as a primitive cubic lattice. The particles are identical and have the same position in the crystal structure. This means that the arrangement of particles follows the pattern of AAA.
Option D, which states that the arrangement of particles follows the pattern of AAAC, is correct. This is because the simple cubic lattice has one particle at each corner of the cube and one particle at the center of the cube. The arrangement of particles in this lattice follows the pattern of AAAC, where A represents the particles.
Conclusion
The arrangement of particles in a simple cubic lattice follows the pattern of AAAC, where A represents the particles. This arrangement is known as a primitive cubic lattice.
A simple cubic lattice is a type of crystal structure where particles are arranged in a cubic pattern with one particle at each corner of the cube. The arrangement is known as a primitive cubic lattice.
Arrangement of Particles
The arrangement of particles in a simple cubic lattice follows the pattern of AAA. This means that all particles (atoms or ions) in the lattice are identical and have the same position in the crystal structure.
Explanation
In a simple cubic lattice, the particles are arranged in a cubic pattern with one particle at each corner of the cube. This arrangement is known as a primitive cubic lattice. The particles are identical and have the same position in the crystal structure. This means that the arrangement of particles follows the pattern of AAA.
Option D, which states that the arrangement of particles follows the pattern of AAAC, is correct. This is because the simple cubic lattice has one particle at each corner of the cube and one particle at the center of the cube. The arrangement of particles in this lattice follows the pattern of AAAC, where A represents the particles.
Conclusion
The arrangement of particles in a simple cubic lattice follows the pattern of AAAC, where A represents the particles. This arrangement is known as a primitive cubic lattice.
What is the minimum number of reactions required for the conversion of aniline to 1,3,5-tribromobenzene?- a)2
- b)3
- c)4
- d)5
Correct answer is option 'B'. Can you explain this answer?
What is the minimum number of reactions required for the conversion of aniline to 1,3,5-tribromobenzene?
a)
2
b)
3
c)
4
d)
5
|
Sravya Datta answered |
To convert aniline to 1,3,5-tribromobenzene, a series of reactions are required. Let's break down the process step by step:
Step 1: Nitration of Aniline
The first reaction involves the nitration of aniline to form 2-nitroaniline. This reaction is carried out by treating aniline with a mixture of concentrated nitric acid (HNO3) and concentrated sulfuric acid (H2SO4).
Step 2: Reduction of 2-Nitroaniline
The next step involves the reduction of 2-nitroaniline to form 1,3-diaminobenzene (also known as m-phenylenediamine). This reaction can be achieved by using a reducing agent like zinc dust in the presence of hydrochloric acid (HCl).
Step 3: Bromination of 1,3-Diaminobenzene
In this step, 1,3-diaminobenzene is brominated to form 1,3-dibromobenzene. This reaction is carried out by treating 1,3-diaminobenzene with bromine (Br2) in the presence of a suitable solvent, such as carbon tetrachloride (CCl4).
Step 4: Bromination of 1,3-Dibromobenzene
The final step involves the bromination of 1,3-dibromobenzene to form 1,3,5-tribromobenzene. This reaction can be achieved by treating 1,3-dibromobenzene with bromine (Br2) in the presence of a Lewis acid catalyst, such as iron (III) bromide (FeBr3).
Thus, a total of 3 reactions are required to convert aniline to 1,3,5-tribromobenzene. Therefore, the correct answer is option B) 3.
Step 1: Nitration of Aniline
The first reaction involves the nitration of aniline to form 2-nitroaniline. This reaction is carried out by treating aniline with a mixture of concentrated nitric acid (HNO3) and concentrated sulfuric acid (H2SO4).
Step 2: Reduction of 2-Nitroaniline
The next step involves the reduction of 2-nitroaniline to form 1,3-diaminobenzene (also known as m-phenylenediamine). This reaction can be achieved by using a reducing agent like zinc dust in the presence of hydrochloric acid (HCl).
Step 3: Bromination of 1,3-Diaminobenzene
In this step, 1,3-diaminobenzene is brominated to form 1,3-dibromobenzene. This reaction is carried out by treating 1,3-diaminobenzene with bromine (Br2) in the presence of a suitable solvent, such as carbon tetrachloride (CCl4).
Step 4: Bromination of 1,3-Dibromobenzene
The final step involves the bromination of 1,3-dibromobenzene to form 1,3,5-tribromobenzene. This reaction can be achieved by treating 1,3-dibromobenzene with bromine (Br2) in the presence of a Lewis acid catalyst, such as iron (III) bromide (FeBr3).
Thus, a total of 3 reactions are required to convert aniline to 1,3,5-tribromobenzene. Therefore, the correct answer is option B) 3.
Diazonium salts are specifically used as intermediates in the production of which of the following compounds?- a)m-Bromotoluene
- b)o-Bromotoluene
- c)p-Bromophenol
- d)o-Bromophenol
Correct answer is option 'A'. Can you explain this answer?
Diazonium salts are specifically used as intermediates in the production of which of the following compounds?
a)
m-Bromotoluene
b)
o-Bromotoluene
c)
p-Bromophenol
d)
o-Bromophenol
|
|
Dipika Rane answered |
Explanation:
Diazonium salts as intermediates:
- Diazonium salts are specifically used as intermediates in the production of m-Bromotoluene.
- During the Sandmeyer reaction, aniline is converted to diazonium salt, which is then reacted with cuprous bromide or cuprous bromide and copper powder to form m-Bromotoluene.
m-Bromotoluene:
- m-Bromotoluene is an important chemical compound used in the production of various organic compounds.
- It is commonly used in the synthesis of pharmaceuticals, dyes, and other organic chemicals.
Role of diazonium salts:
- Diazonium salts play a crucial role in the Sandmeyer reaction, where they are used as intermediates to introduce various functional groups, such as bromine, into aromatic compounds.
- In the case of m-Bromotoluene, diazonium salts are essential for the conversion of aniline to the desired brominated product.
Importance of intermediates:
- Intermediates like diazonium salts allow for the controlled and selective introduction of specific functional groups into organic molecules.
- They serve as key building blocks in organic synthesis, enabling the synthesis of a wide range of complex organic compounds.
Therefore, diazonium salts are crucial intermediates in the production of m-Bromotoluene, playing a significant role in the synthesis of various organic compounds.
Diazonium salts as intermediates:
- Diazonium salts are specifically used as intermediates in the production of m-Bromotoluene.
- During the Sandmeyer reaction, aniline is converted to diazonium salt, which is then reacted with cuprous bromide or cuprous bromide and copper powder to form m-Bromotoluene.
m-Bromotoluene:
- m-Bromotoluene is an important chemical compound used in the production of various organic compounds.
- It is commonly used in the synthesis of pharmaceuticals, dyes, and other organic chemicals.
Role of diazonium salts:
- Diazonium salts play a crucial role in the Sandmeyer reaction, where they are used as intermediates to introduce various functional groups, such as bromine, into aromatic compounds.
- In the case of m-Bromotoluene, diazonium salts are essential for the conversion of aniline to the desired brominated product.
Importance of intermediates:
- Intermediates like diazonium salts allow for the controlled and selective introduction of specific functional groups into organic molecules.
- They serve as key building blocks in organic synthesis, enabling the synthesis of a wide range of complex organic compounds.
Therefore, diazonium salts are crucial intermediates in the production of m-Bromotoluene, playing a significant role in the synthesis of various organic compounds.
Diazonium salts are primarily used for the preparation of _______ substituted aromatic compounds.- a)alkyl
- b)halogen
- c)amino
- d)COOH
Correct answer is option 'B'. Can you explain this answer?
Diazonium salts are primarily used for the preparation of _______ substituted aromatic compounds.
a)
alkyl
b)
halogen
c)
amino
d)
COOH
|
Bhavya Joshi answered |
Diazonium salts are primarily used for the preparation of halogen-substituted aromatic compounds. Diazonium salts are a class of organic compounds that contain a positively charged diazonium group (N2+) attached to an aromatic ring. These salts are highly reactive and can undergo various chemical reactions to modify the aromatic ring.
Diazonium salts can be prepared by the reaction of primary aromatic amines with nitrous acid. This reaction is known as diazotization and involves the conversion of the amino group (-NH2) into a diazonium group (-N2+). The diazonium salt formed can then be used for further reactions.
The most common reaction involving diazonium salts is the Sandmeyer reaction. In this reaction, the diazonium salt is reacted with a copper(I) halide (CuX) to substitute the diazonium group with a halogen atom (X). For example, when a diazonium salt is treated with copper(I) chloride (CuCl), the diazonium group is replaced by a chlorine atom, resulting in the formation of a chloro-substituted aromatic compound.
Another reaction that can be carried out using diazonium salts is the Gattermann reaction. In this reaction, the diazonium salt is treated with hydrogen cyanide (HCN) and a catalyst such as copper(I) chloride (CuCl) to substitute the diazonium group with a cyano group (-CN). This results in the formation of a cyanide-substituted aromatic compound.
Diazonium salts can also undergo other reactions such as coupling reactions, where they react with aromatic compounds or phenols to form azo compounds or phenol ethers, respectively. These reactions allow for the introduction of various functional groups onto the aromatic ring.
In summary, diazonium salts are primarily used for the preparation of halogen-substituted aromatic compounds. They can undergo reactions such as the Sandmeyer reaction and the Gattermann reaction to substitute the diazonium group with halogens or other functional groups. These reactions allow for the synthesis of a wide range of substituted aromatic compounds with different properties and applications.
Diazonium salts can be prepared by the reaction of primary aromatic amines with nitrous acid. This reaction is known as diazotization and involves the conversion of the amino group (-NH2) into a diazonium group (-N2+). The diazonium salt formed can then be used for further reactions.
The most common reaction involving diazonium salts is the Sandmeyer reaction. In this reaction, the diazonium salt is reacted with a copper(I) halide (CuX) to substitute the diazonium group with a halogen atom (X). For example, when a diazonium salt is treated with copper(I) chloride (CuCl), the diazonium group is replaced by a chlorine atom, resulting in the formation of a chloro-substituted aromatic compound.
Another reaction that can be carried out using diazonium salts is the Gattermann reaction. In this reaction, the diazonium salt is treated with hydrogen cyanide (HCN) and a catalyst such as copper(I) chloride (CuCl) to substitute the diazonium group with a cyano group (-CN). This results in the formation of a cyanide-substituted aromatic compound.
Diazonium salts can also undergo other reactions such as coupling reactions, where they react with aromatic compounds or phenols to form azo compounds or phenol ethers, respectively. These reactions allow for the introduction of various functional groups onto the aromatic ring.
In summary, diazonium salts are primarily used for the preparation of halogen-substituted aromatic compounds. They can undergo reactions such as the Sandmeyer reaction and the Gattermann reaction to substitute the diazonium group with halogens or other functional groups. These reactions allow for the synthesis of a wide range of substituted aromatic compounds with different properties and applications.
Which of the following reactions/tests does not help in the distinction between ethylamine and diethylamine?- a)Carbylamine test
- b)Hinsberg’s test
- c)Reaction with HNO2
- d)Reaction with CH3CH2Br
Correct answer is option 'D'. Can you explain this answer?
Which of the following reactions/tests does not help in the distinction between ethylamine and diethylamine?
a)
Carbylamine test
b)
Hinsberg’s test
c)
Reaction with HNO2
d)
Reaction with CH3CH2Br
|
|
Shalini Patel answered |
Both ethylamine and diethylamine on reaction with CH3CH2Br eventually gives quaternary ammonium salt. Hence, the alkylation of primary amines cannot be used as a distinction method.
Which is the largest halogen atom?- a)Bromine
- b)Chlorine
- c)Fluorine
- d)Iodine
Correct answer is option 'D'. Can you explain this answer?
Which is the largest halogen atom?
a)
Bromine
b)
Chlorine
c)
Fluorine
d)
Iodine
|
Amrita Sarkar answered |
Iodine (I) is the largest halogen atom.
Explanation:
1. The Halogens:
The halogens are a group of elements in the periodic table known as Group 17 or Group VIIA. They include fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). These elements are highly reactive nonmetals and are known for their ability to form halide ions by gaining one electron.
2. Atomic Radius:
The atomic radius is a measure of the size of an atom. It is defined as the distance between the nucleus of an atom and its outermost electron. As we move down a group in the periodic table, the atomic radius generally increases. This is because each successive element has an additional electron shell, which increases the distance between the nucleus and the outermost electrons.
3. Comparison of Atomic Radii:
To determine which halogen atom is the largest, we need to compare their atomic radii.
- Fluorine (F) has the smallest atomic radius among the halogens due to its high effective nuclear charge.
- Chlorine (Cl) is larger than fluorine because it has an additional electron shell.
- Bromine (Br) is larger than chlorine because it has an additional electron shell.
- Iodine (I) is the largest halogen atom because it has an additional electron shell compared to bromine.
Therefore, the correct answer is option 'D', iodine (I), as it has the largest atomic radius among the halogens.
Summary:
Iodine (I) is the largest halogen atom due to its additional electron shell compared to fluorine, chlorine, and bromine. The atomic radius generally increases as we move down the halogen group in the periodic table.
Explanation:
1. The Halogens:
The halogens are a group of elements in the periodic table known as Group 17 or Group VIIA. They include fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). These elements are highly reactive nonmetals and are known for their ability to form halide ions by gaining one electron.
2. Atomic Radius:
The atomic radius is a measure of the size of an atom. It is defined as the distance between the nucleus of an atom and its outermost electron. As we move down a group in the periodic table, the atomic radius generally increases. This is because each successive element has an additional electron shell, which increases the distance between the nucleus and the outermost electrons.
3. Comparison of Atomic Radii:
To determine which halogen atom is the largest, we need to compare their atomic radii.
- Fluorine (F) has the smallest atomic radius among the halogens due to its high effective nuclear charge.
- Chlorine (Cl) is larger than fluorine because it has an additional electron shell.
- Bromine (Br) is larger than chlorine because it has an additional electron shell.
- Iodine (I) is the largest halogen atom because it has an additional electron shell compared to bromine.
Therefore, the correct answer is option 'D', iodine (I), as it has the largest atomic radius among the halogens.
Summary:
Iodine (I) is the largest halogen atom due to its additional electron shell compared to fluorine, chlorine, and bromine. The atomic radius generally increases as we move down the halogen group in the periodic table.
Which of the following ores are concentrated by froth flotation?- a)Haematite
- b)Zinc
- c)Copper pyrites
- d)Magnetite
Correct answer is option 'C'. Can you explain this answer?
Which of the following ores are concentrated by froth flotation?
a)
Haematite
b)
Zinc
c)
Copper pyrites
d)
Magnetite
|
|
Siddharth Tiwari answered |
Froth flotation is a common method used for the concentration of ores. It is based on the principle of preferential wetting of the ore particles by oil and water, where the ore particles are selectively attached to the air bubbles and carried to the surface of the flotation cell, while the gangue particles remain in the bulk solution. In this process, various reagents are used to modify the surface properties of the ore particles and create a froth that can be easily removed.
Among the given options, copper pyrites is the only ore that is concentrated by froth flotation. Here's why:
Copper pyrites:
- Copper pyrites, also known as chalcopyrite (CuFeS2), is a sulfide ore that contains copper, iron, and sulfur.
- The ore particles of copper pyrites are relatively large and have a high density compared to the gangue minerals.
- In froth flotation, the ore is first crushed and ground to a fine size, and then mixed with water and various reagents to create a slurry.
- The slurry is then agitated and air is blown into it to create air bubbles.
- The reagents, known as collectors, are added to the slurry to selectively adsorb on the surface of the copper pyrites particles, making them hydrophobic (water-repellent).
- Frothers are also added to stabilize the froth and enhance the attachment of the air bubbles to the hydrophobic particles.
- When air bubbles are introduced into the slurry, they attach to the hydrophobic copper pyrites particles and carry them to the surface as a froth.
- The froth is then skimmed off and the concentrated copper pyrites is obtained.
- The gangue minerals, which are hydrophilic (water-loving), remain in the bulk solution and are discarded as tailings.
Other options:
- Haematite: Haematite (Fe2O3) is an oxide ore of iron and is not concentrated by froth flotation. It is typically concentrated by magnetic separation or gravity separation methods.
- Zinc: Zinc ores, such as sphalerite (ZnS), are also not concentrated by froth flotation. They are typically concentrated by froth flotation followed by roasting to convert the zinc sulfide to zinc oxide, which is then reduced to metallic zinc.
- Magnetite: Magnetite (Fe3O4) is an oxide ore of iron and is not concentrated by froth flotation. It is typically concentrated by magnetic separation or gravity separation methods.
Therefore, among the given options, only copper pyrites is concentrated by froth flotation.
Among the given options, copper pyrites is the only ore that is concentrated by froth flotation. Here's why:
Copper pyrites:
- Copper pyrites, also known as chalcopyrite (CuFeS2), is a sulfide ore that contains copper, iron, and sulfur.
- The ore particles of copper pyrites are relatively large and have a high density compared to the gangue minerals.
- In froth flotation, the ore is first crushed and ground to a fine size, and then mixed with water and various reagents to create a slurry.
- The slurry is then agitated and air is blown into it to create air bubbles.
- The reagents, known as collectors, are added to the slurry to selectively adsorb on the surface of the copper pyrites particles, making them hydrophobic (water-repellent).
- Frothers are also added to stabilize the froth and enhance the attachment of the air bubbles to the hydrophobic particles.
- When air bubbles are introduced into the slurry, they attach to the hydrophobic copper pyrites particles and carry them to the surface as a froth.
- The froth is then skimmed off and the concentrated copper pyrites is obtained.
- The gangue minerals, which are hydrophilic (water-loving), remain in the bulk solution and are discarded as tailings.
Other options:
- Haematite: Haematite (Fe2O3) is an oxide ore of iron and is not concentrated by froth flotation. It is typically concentrated by magnetic separation or gravity separation methods.
- Zinc: Zinc ores, such as sphalerite (ZnS), are also not concentrated by froth flotation. They are typically concentrated by froth flotation followed by roasting to convert the zinc sulfide to zinc oxide, which is then reduced to metallic zinc.
- Magnetite: Magnetite (Fe3O4) is an oxide ore of iron and is not concentrated by froth flotation. It is typically concentrated by magnetic separation or gravity separation methods.
Therefore, among the given options, only copper pyrites is concentrated by froth flotation.
Which of the following is a substrate specific enzyme?- a)Maltase
- b)Carboxylase
- c)Hexokinase
- d)Carbonic anhydrase
Correct answer is option 'A'. Can you explain this answer?
Which of the following is a substrate specific enzyme?
a)
Maltase
b)
Carboxylase
c)
Hexokinase
d)
Carbonic anhydrase
|
|
Shalini Patel answered |
Substrate specific enzymes are those which can act only on one particular compound to give a product(s). For example, maltase acts only on maltose to break the glycosidic linkage between the two glucose units.
What is the first element of the fourth transition series in the periodic table?- a)Scandium
- b)Yttrium
- c)Actinium
- d)Lanthanum
Correct answer is option 'C'. Can you explain this answer?
What is the first element of the fourth transition series in the periodic table?
a)
Scandium
b)
Yttrium
c)
Actinium
d)
Lanthanum
|
Naina Menon answered |
Explanation:
The fourth transition series in the periodic table refers to the elements that fill the 5f orbitals. These elements are part of the actinide series and are commonly referred to as the actinides. The first element in this series is actinium, which has the atomic number 89 and the symbol Ac.
Actinium (Ac):
- Actinium is a radioactive element that belongs to the actinide series.
- It was discovered in 1899 by André-Louis Debierne, a French chemist.
- Actinium is a silvery-white metal that tarnishes in air.
- It has a relatively short half-life of about 21.8 years, and it decays into thorium-227 through alpha decay.
- Actinium is primarily used for scientific research and in small quantities for medical purposes, such as in radiotherapy.
Comparison with other options:
- Scandium (Sc) belongs to the third transition series and is not part of the actinide series.
- Yttrium (Y) also belongs to the third transition series and is not part of the actinide series.
- Lanthanum (La) belongs to the second transition series and is not part of the actinide series.
Therefore, the correct answer is option 'c) Actinium' as it is the first element of the fourth transition series in the periodic table.
The fourth transition series in the periodic table refers to the elements that fill the 5f orbitals. These elements are part of the actinide series and are commonly referred to as the actinides. The first element in this series is actinium, which has the atomic number 89 and the symbol Ac.
Actinium (Ac):
- Actinium is a radioactive element that belongs to the actinide series.
- It was discovered in 1899 by André-Louis Debierne, a French chemist.
- Actinium is a silvery-white metal that tarnishes in air.
- It has a relatively short half-life of about 21.8 years, and it decays into thorium-227 through alpha decay.
- Actinium is primarily used for scientific research and in small quantities for medical purposes, such as in radiotherapy.
Comparison with other options:
- Scandium (Sc) belongs to the third transition series and is not part of the actinide series.
- Yttrium (Y) also belongs to the third transition series and is not part of the actinide series.
- Lanthanum (La) belongs to the second transition series and is not part of the actinide series.
Therefore, the correct answer is option 'c) Actinium' as it is the first element of the fourth transition series in the periodic table.
Which of the following statements is false?- a)Salt water decelerates the rate of corrosion
- b)Magnesium is more active than iron
- c)During galvanization, ZnCO3.Zn(OH)2 is formed which prevent further corrosion
- d)Anti-rust solutions are used in car radiators to prevent rusting of iron parts of the engine
Correct answer is option 'A'. Can you explain this answer?
Which of the following statements is false?
a)
Salt water decelerates the rate of corrosion
b)
Magnesium is more active than iron
c)
During galvanization, ZnCO3.Zn(OH)2 is formed which prevent further corrosion
d)
Anti-rust solutions are used in car radiators to prevent rusting of iron parts of the engine
|
Pragati Nair answered |
False statement: Salt water decelerates the rate of corrosion
Explanation:
- Corrosion is the process in which metals react with substances in the environment, such as oxygen and water, leading to their deterioration and loss of structural integrity.
- Saltwater is actually more corrosive than pure water because it contains dissolved salts, primarily sodium chloride (NaCl).
- When metal is exposed to saltwater, it enhances the corrosion process due to the presence of ions in the solution, which increases the electrical conductivity and accelerates the rate of corrosion.
- The ions in saltwater provide a pathway for the flow of electrons, creating a galvanic cell or battery-like setup, which leads to accelerated metal corrosion.
- This process is known as galvanic corrosion, and it occurs when two dissimilar metals are in contact with an electrolyte, such as saltwater.
- In the galvanic cell, the more active metal (such as magnesium) acts as an anode and undergoes oxidation, while the less active metal (such as iron) acts as a cathode and undergoes reduction.
- This leads to the accelerated corrosion of the anode (magnesium) and the protection of the cathode (iron), resulting in the degradation of the more active metal.
- Therefore, statement a) "Saltwater decelerates the rate of corrosion" is false because saltwater actually accelerates the rate of corrosion due to the presence of ions, leading to galvanic corrosion.
Explanation:
- Corrosion is the process in which metals react with substances in the environment, such as oxygen and water, leading to their deterioration and loss of structural integrity.
- Saltwater is actually more corrosive than pure water because it contains dissolved salts, primarily sodium chloride (NaCl).
- When metal is exposed to saltwater, it enhances the corrosion process due to the presence of ions in the solution, which increases the electrical conductivity and accelerates the rate of corrosion.
- The ions in saltwater provide a pathway for the flow of electrons, creating a galvanic cell or battery-like setup, which leads to accelerated metal corrosion.
- This process is known as galvanic corrosion, and it occurs when two dissimilar metals are in contact with an electrolyte, such as saltwater.
- In the galvanic cell, the more active metal (such as magnesium) acts as an anode and undergoes oxidation, while the less active metal (such as iron) acts as a cathode and undergoes reduction.
- This leads to the accelerated corrosion of the anode (magnesium) and the protection of the cathode (iron), resulting in the degradation of the more active metal.
- Therefore, statement a) "Saltwater decelerates the rate of corrosion" is false because saltwater actually accelerates the rate of corrosion due to the presence of ions, leading to galvanic corrosion.
What is the preferred electrode when it is not allowed to take part in the chemical reaction?- a)Gold
- b)Silver
- c)Copper
- d)Graphite
Correct answer is option 'D'. Can you explain this answer?
What is the preferred electrode when it is not allowed to take part in the chemical reaction?
a)
Gold
b)
Silver
c)
Copper
d)
Graphite
|
Mainak Sengupta answered |
Introduction:
When an electrode is not allowed to take part in a chemical reaction, it is referred to as an inert electrode. Inert electrodes are commonly used in electrochemical cells where the focus is on the reaction occurring in the solution rather than at the electrode itself. Among the given options, graphite is the preferred electrode when it is not allowed to take part in the chemical reaction.
Explanation:
Graphite is a form of carbon that is electrically conductive and chemically stable. It possesses several properties that make it suitable as an inert electrode:
1. Electrical conductivity:
Graphite is an excellent conductor of electricity due to its unique structure and electron configuration. It allows the flow of electrons without participating in the chemical reactions occurring in the cell.
2. Chemical stability:
Graphite is highly stable and does not readily react with most substances. It is resistant to oxidation, corrosion, and degradation when exposed to various electrolytes and reaction conditions.
3. Non-reactivity:
Graphite does not readily undergo redox reactions or ionization in the electrochemical cell. It remains unchanged during the course of the reaction, ensuring that the electrode does not interfere with the desired chemical reactions.
4. Wide potential range:
Graphite electrodes can operate over a wide range of potentials, allowing for the study and analysis of various electrochemical systems. This versatility makes them suitable for a wide range of applications.
5. Availability and cost-effectiveness:
Graphite is a readily available and cost-effective material, making it a popular choice for inert electrodes in both research and industrial settings.
Conclusion:
In conclusion, graphite is the preferred electrode when it is not allowed to take part in the chemical reaction due to its excellent electrical conductivity, chemical stability, non-reactivity, wide potential range, and cost-effectiveness. It is commonly used as an inert electrode in electrochemical cells to ensure accurate analysis and measurement of the desired chemical reactions occurring in the solution.
When an electrode is not allowed to take part in a chemical reaction, it is referred to as an inert electrode. Inert electrodes are commonly used in electrochemical cells where the focus is on the reaction occurring in the solution rather than at the electrode itself. Among the given options, graphite is the preferred electrode when it is not allowed to take part in the chemical reaction.
Explanation:
Graphite is a form of carbon that is electrically conductive and chemically stable. It possesses several properties that make it suitable as an inert electrode:
1. Electrical conductivity:
Graphite is an excellent conductor of electricity due to its unique structure and electron configuration. It allows the flow of electrons without participating in the chemical reactions occurring in the cell.
2. Chemical stability:
Graphite is highly stable and does not readily react with most substances. It is resistant to oxidation, corrosion, and degradation when exposed to various electrolytes and reaction conditions.
3. Non-reactivity:
Graphite does not readily undergo redox reactions or ionization in the electrochemical cell. It remains unchanged during the course of the reaction, ensuring that the electrode does not interfere with the desired chemical reactions.
4. Wide potential range:
Graphite electrodes can operate over a wide range of potentials, allowing for the study and analysis of various electrochemical systems. This versatility makes them suitable for a wide range of applications.
5. Availability and cost-effectiveness:
Graphite is a readily available and cost-effective material, making it a popular choice for inert electrodes in both research and industrial settings.
Conclusion:
In conclusion, graphite is the preferred electrode when it is not allowed to take part in the chemical reaction due to its excellent electrical conductivity, chemical stability, non-reactivity, wide potential range, and cost-effectiveness. It is commonly used as an inert electrode in electrochemical cells to ensure accurate analysis and measurement of the desired chemical reactions occurring in the solution.
What is the integrated rate equation for a first order reaction?- a)[A] = [A]0e-kt
- b)[A] = [A]0/e-kt
- c)[A] = [A]0e-t
- d)[A] = [A]0e-k
Correct answer is option 'A'. Can you explain this answer?
What is the integrated rate equation for a first order reaction?
a)
[A] = [A]0e-kt
b)
[A] = [A]0/e-kt
c)
[A] = [A]0e-t
d)
[A] = [A]0e-k
|
|
Tanuja Kapoor answered |
A reaction is said to be of the first order if the rate of the reaction depends upon one concentration term only. The integrated rate equation for a first order reaction in exponential form is [A] = [A]0e-kt.
If, at 298 K water is the solvent, and Henry’s law constant for CO2 is 1.67 kbar and the constant of argon is 40.3 kbar, which of the following statements is true?- a)Argon is more soluble than CO2
- b)Argon is less soluble than CO2
- c)Argon is insoluble in water
- d)Argon and CO2 are equally soluble
Correct answer is option 'B'. Can you explain this answer?
If, at 298 K water is the solvent, and Henry’s law constant for CO2 is 1.67 kbar and the constant of argon is 40.3 kbar, which of the following statements is true?
a)
Argon is more soluble than CO2
b)
Argon is less soluble than CO2
c)
Argon is insoluble in water
d)
Argon and CO2 are equally soluble
|
Kalyan Chavan answered |
's law constant for oxygen is 1.2 x 10^-3 M/atm, calculate the solubility of oxygen in water when the partial pressure of oxygen is 0.8 atm.
According to Henry's law, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid. The proportionality constant is known as Henry's law constant.
Using Henry's law equation:
C = kH * P
where C is the concentration of the gas in the liquid, kH is Henry's law constant, and P is the partial pressure of the gas above the liquid.
Given:
kH for oxygen = 1.2 x 10^-3 M/atm
P = 0.8 atm
We need to find the solubility of oxygen in water at 298 K.
Substituting the given values in the equation:
C = kH * P
C = 1.2 x 10^-3 M/atm * 0.8 atm
C = 9.6 x 10^-4 M
Therefore, the solubility of oxygen in water at 298 K when the partial pressure of oxygen is 0.8 atm is 9.6 x 10^-4 M.
According to Henry's law, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid. The proportionality constant is known as Henry's law constant.
Using Henry's law equation:
C = kH * P
where C is the concentration of the gas in the liquid, kH is Henry's law constant, and P is the partial pressure of the gas above the liquid.
Given:
kH for oxygen = 1.2 x 10^-3 M/atm
P = 0.8 atm
We need to find the solubility of oxygen in water at 298 K.
Substituting the given values in the equation:
C = kH * P
C = 1.2 x 10^-3 M/atm * 0.8 atm
C = 9.6 x 10^-4 M
Therefore, the solubility of oxygen in water at 298 K when the partial pressure of oxygen is 0.8 atm is 9.6 x 10^-4 M.
Which of the following are not supposed to treat humans directly?- a)Disinfectants
- b)Antimalarials
- c)Antiseptics
- d)Antibiotics
Correct answer is option 'A'. Can you explain this answer?
Which of the following are not supposed to treat humans directly?
a)
Disinfectants
b)
Antimalarials
c)
Antiseptics
d)
Antibiotics
|
Preeti Khanna answered |
Antimalarials and antibiotics are ingested in the form of pills. Antiseptics are applied on the skin. Disinfectants are used for cleaning objects like floors, toilets, drains, etc. and protect them from pathogenic activity.
For a reaction A +B → C, the experimental rate law is found to be R=k[A]1[B]1/2. Find the rate of the reaction when [A] = 0.5 M, [B] = 0.1 M and k=0.03.- a)4.74 × 10-2 (L/mol)1/2 s-1
- b)4.74 × 10-2 (L/mol)1/2 s-2
- c)5.748 × 10-2 (L/mol)1/2 s-1
- d)4.86 × 10-2 (L/mol)1/2 s-1
Correct answer is option 'A'. Can you explain this answer?
For a reaction A +B → C, the experimental rate law is found to be R=k[A]1[B]1/2. Find the rate of the reaction when [A] = 0.5 M, [B] = 0.1 M and k=0.03.
a)
4.74 × 10-2 (L/mol)1/2 s-1
b)
4.74 × 10-2 (L/mol)1/2 s-2
c)
5.748 × 10-2 (L/mol)1/2 s-1
d)
4.86 × 10-2 (L/mol)1/2 s-1
|
|
Suresh Iyer answered |
Given, [A] = 0.5 M, [B] = 0.1 M and k= 0.03
From the rate law it is evident that the order of the reaction is 1+ 0.5 = 1.5 = 32
Therefore the unit of k= (mol L-1)1-1.5 s-1 = (L/mol)1/2 s-1
R= k[A]1[B]1/2 = 0.03 × 0.5 × 0.11/2 = 4.74 × 10-2(L/mol)1/2 s-1.
From the rate law it is evident that the order of the reaction is 1+ 0.5 = 1.5 = 32
Therefore the unit of k= (mol L-1)1-1.5 s-1 = (L/mol)1/2 s-1
R= k[A]1[B]1/2 = 0.03 × 0.5 × 0.11/2 = 4.74 × 10-2(L/mol)1/2 s-1.
Hydrolysis of the adduct formed form the reaction of ________ with methyl magnesium bromide gives 2-Methylpropan-2-ol.- a)Methanal
- b)Ethanal
- c)Propanal
- d)Propanone
Correct answer is option 'D'. Can you explain this answer?
Hydrolysis of the adduct formed form the reaction of ________ with methyl magnesium bromide gives 2-Methylpropan-2-ol.
a)
Methanal
b)
Ethanal
c)
Propanal
d)
Propanone
|
|
Anshika Menon answered |
Hydrolysis of the adduct formed from the reaction of Propanone with methyl magnesium bromide
Propanone reacts with methyl magnesium bromide (CH3MgBr) to form an adduct. The reaction forms a magnesium alkoxide intermediate, which then reacts with water in the hydrolysis step to give 2-Methylpropan-2-ol.
Reaction:
Propanone + CH3MgBr → Adduct
Adduct + H2O → 2-Methylpropan-2-ol
Explanation:
- Propanone (also known as acetone) reacts with methyl magnesium bromide to form an adduct through a nucleophilic addition reaction.
- The adduct formed is then hydrolyzed by water to give 2-Methylpropan-2-ol.
- The hydrolysis step involves breaking the bond between the carbon and magnesium in the adduct, followed by the addition of a hydroxyl group to one of the carbons to form the alcohol product.
- The final product, 2-Methylpropan-2-ol, is a tertiary alcohol with a branched structure.
Conclusion:
The hydrolysis of the adduct formed from the reaction of Propanone with methyl magnesium bromide results in the formation of 2-Methylpropan-2-ol, a tertiary alcohol. This reaction demonstrates the versatility of organometallic reagents like Grignard reagents in organic synthesis.
Propanone reacts with methyl magnesium bromide (CH3MgBr) to form an adduct. The reaction forms a magnesium alkoxide intermediate, which then reacts with water in the hydrolysis step to give 2-Methylpropan-2-ol.
Reaction:
Propanone + CH3MgBr → Adduct
Adduct + H2O → 2-Methylpropan-2-ol
Explanation:
- Propanone (also known as acetone) reacts with methyl magnesium bromide to form an adduct through a nucleophilic addition reaction.
- The adduct formed is then hydrolyzed by water to give 2-Methylpropan-2-ol.
- The hydrolysis step involves breaking the bond between the carbon and magnesium in the adduct, followed by the addition of a hydroxyl group to one of the carbons to form the alcohol product.
- The final product, 2-Methylpropan-2-ol, is a tertiary alcohol with a branched structure.
Conclusion:
The hydrolysis of the adduct formed from the reaction of Propanone with methyl magnesium bromide results in the formation of 2-Methylpropan-2-ol, a tertiary alcohol. This reaction demonstrates the versatility of organometallic reagents like Grignard reagents in organic synthesis.
Which of the following is the correct order of arrangement of the first five lanthanides according to atomic number?- a)La, Ce, Pr, Nd, Pm
- b)La, Pr, Ce, Pm, Nd
- c)La, Pr, Ce, Nd, Pm
- d)La, Ce, Pr, Pm, Nd
Correct answer is option 'A'. Can you explain this answer?
Which of the following is the correct order of arrangement of the first five lanthanides according to atomic number?
a)
La, Ce, Pr, Nd, Pm
b)
La, Pr, Ce, Pm, Nd
c)
La, Pr, Ce, Nd, Pm
d)
La, Ce, Pr, Pm, Nd
|
|
Nandini Iyer answered |
The first five elements of Lanthanides are:
Lanthanum (La) – 57
Cerium (Ce) – 58
Praseodymium (Pr) – 59
Neodymium (Nd) – 60
Promethium (Pm) – 61.
Lanthanum (La) – 57
Cerium (Ce) – 58
Praseodymium (Pr) – 59
Neodymium (Nd) – 60
Promethium (Pm) – 61.
What shape is the HNO3 molecule in its gaseous state?- a)Bent
- b)Linear
- c)Planar
- d)See Saw
Correct answer is option 'C'. Can you explain this answer?
What shape is the HNO3 molecule in its gaseous state?
a)
Bent
b)
Linear
c)
Planar
d)
See Saw
|
|
Pragati Choudhury answered |
The HNO3 molecule, which is also known as nitric acid, consists of one hydrogen atom (H), one nitrogen atom (N), and three oxygen atoms (O). In its gaseous state, HNO3 adopts a planar shape.
Explanation:
- HNO3 contains a central nitrogen atom (N) surrounded by three oxygen atoms (O) and one hydrogen atom (H).
- The nitrogen atom has five valence electrons, while each oxygen atom has six valence electrons. The hydrogen atom contributes one valence electron.
- In order to determine the shape of the molecule, we need to consider the arrangement of the atoms and the number of electron pairs around the central atom.
- The nitrogen atom in HNO3 is sp2 hybridized, which means it forms three sigma bonds with three oxygen atoms.
- The oxygen atoms are also sp2 hybridized and form sigma bonds with the nitrogen atom.
- The hydrogen atom is attached to one of the oxygen atoms through a sigma bond.
- The electron pair geometry around the nitrogen atom is trigonal planar, as it has three regions of electron density (three sigma bonds).
- The molecular geometry, also known as the shape, is determined by considering the electron pairs and the atoms bonded to the central atom.
- In this case, the molecular geometry is also planar, as all the atoms and electron pairs are in the same plane.
- Thus, the HNO3 molecule in its gaseous state adopts a planar shape.
- The planar shape of HNO3 can be visualized as a flat molecule with the nitrogen atom at the center and the three oxygen atoms and one hydrogen atom arranged in a flat plane around it.
Explanation:
- HNO3 contains a central nitrogen atom (N) surrounded by three oxygen atoms (O) and one hydrogen atom (H).
- The nitrogen atom has five valence electrons, while each oxygen atom has six valence electrons. The hydrogen atom contributes one valence electron.
- In order to determine the shape of the molecule, we need to consider the arrangement of the atoms and the number of electron pairs around the central atom.
- The nitrogen atom in HNO3 is sp2 hybridized, which means it forms three sigma bonds with three oxygen atoms.
- The oxygen atoms are also sp2 hybridized and form sigma bonds with the nitrogen atom.
- The hydrogen atom is attached to one of the oxygen atoms through a sigma bond.
- The electron pair geometry around the nitrogen atom is trigonal planar, as it has three regions of electron density (three sigma bonds).
- The molecular geometry, also known as the shape, is determined by considering the electron pairs and the atoms bonded to the central atom.
- In this case, the molecular geometry is also planar, as all the atoms and electron pairs are in the same plane.
- Thus, the HNO3 molecule in its gaseous state adopts a planar shape.
- The planar shape of HNO3 can be visualized as a flat molecule with the nitrogen atom at the center and the three oxygen atoms and one hydrogen atom arranged in a flat plane around it.
How is the M-C pi bond formed?- a)Donation of electron pair of half-filled metal d orbital to empty bonding pi orbital of CO
- b)Donation of electron pair of filled metal d orbital to empty bonding pi orbital of CO
- c)Donation of electron pair of filled metal d orbital to empty antibonding pi orbital of CO
- d)Donation of electron pair of half-filled metal d orbital to empty antibonding pi orbital of CO
Correct answer is option 'C'. Can you explain this answer?
How is the M-C pi bond formed?
a)
Donation of electron pair of half-filled metal d orbital to empty bonding pi orbital of CO
b)
Donation of electron pair of filled metal d orbital to empty bonding pi orbital of CO
c)
Donation of electron pair of filled metal d orbital to empty antibonding pi orbital of CO
d)
Donation of electron pair of half-filled metal d orbital to empty antibonding pi orbital of CO
|
|
Nandini Iyer answered |
The pi bond involves donation of electrons from filled metal d orbitals into empty antibonding pi orbitals of CO. This is also called a back bond.
What was the term proposed by Werner for the number of groups bound directly to the metal ion in a coordination complex?- a)Primary valence
- b)Secondary valence
- c)Oxidation number
- d)Polyhedra
Correct answer is option 'B'. Can you explain this answer?
What was the term proposed by Werner for the number of groups bound directly to the metal ion in a coordination complex?
a)
Primary valence
b)
Secondary valence
c)
Oxidation number
d)
Polyhedra
|
Akshay Shah answered |
Primary Valence and Secondary Valence
Werner's theory of coordination compounds revolutionized the understanding of complex compounds and their behavior. One of the key concepts proposed by Werner was the idea of primary and secondary valence.
1. Primary Valence:
- The primary valence refers to the total number of ligands directly bound to the central metal ion through coordinate covalent bonds.
- It represents the oxidation state or charge of the metal ion.
- It determines the overall charge of the complex and its stability.
- The primary valence is often determined by the periodic table group number of the metal ion.
2. Secondary Valence:
- The secondary valence, also known as coordination number, refers to the number of groups directly bound to the metal ion in a coordination complex.
- It represents the number of bonds formed by the ligands with the central metal ion.
- The coordination number can vary depending on the metal ion and the ligands involved.
- The coordination number can range from 2 to 12, with common coordination numbers being 4, 6, and 8.
- The coordination number is determined by the electron pair accepting capacity of the metal ion and the electron donor capacity of the ligands.
Proposal of Secondary Valence as the Correct Term:
- Werner proposed the term "secondary valence" to describe the number of groups directly bound to the metal ion in a coordination complex.
- This term is more appropriate because it focuses on the bonding between the metal ion and the ligands.
- It helps to distinguish between the primary valence, which represents the overall charge of the complex, and the secondary valence, which represents the coordination number or the number of bonds formed by the ligands.
- The secondary valence concept is widely used in coordination chemistry to describe the geometry and stability of coordination complexes.
In summary, Werner proposed the term "secondary valence" to describe the number of groups directly bound to the metal ion in a coordination complex. This term focuses on the bonding between the metal ion and the ligands and helps to distinguish it from the primary valence, which represents the overall charge of the complex. The concept of secondary valence is widely used in coordination chemistry to describe the geometry and stability of coordination complexes.
Werner's theory of coordination compounds revolutionized the understanding of complex compounds and their behavior. One of the key concepts proposed by Werner was the idea of primary and secondary valence.
1. Primary Valence:
- The primary valence refers to the total number of ligands directly bound to the central metal ion through coordinate covalent bonds.
- It represents the oxidation state or charge of the metal ion.
- It determines the overall charge of the complex and its stability.
- The primary valence is often determined by the periodic table group number of the metal ion.
2. Secondary Valence:
- The secondary valence, also known as coordination number, refers to the number of groups directly bound to the metal ion in a coordination complex.
- It represents the number of bonds formed by the ligands with the central metal ion.
- The coordination number can vary depending on the metal ion and the ligands involved.
- The coordination number can range from 2 to 12, with common coordination numbers being 4, 6, and 8.
- The coordination number is determined by the electron pair accepting capacity of the metal ion and the electron donor capacity of the ligands.
Proposal of Secondary Valence as the Correct Term:
- Werner proposed the term "secondary valence" to describe the number of groups directly bound to the metal ion in a coordination complex.
- This term is more appropriate because it focuses on the bonding between the metal ion and the ligands.
- It helps to distinguish between the primary valence, which represents the overall charge of the complex, and the secondary valence, which represents the coordination number or the number of bonds formed by the ligands.
- The secondary valence concept is widely used in coordination chemistry to describe the geometry and stability of coordination complexes.
In summary, Werner proposed the term "secondary valence" to describe the number of groups directly bound to the metal ion in a coordination complex. This term focuses on the bonding between the metal ion and the ligands and helps to distinguish it from the primary valence, which represents the overall charge of the complex. The concept of secondary valence is widely used in coordination chemistry to describe the geometry and stability of coordination complexes.
Phenol is approximately how much times acidic than ethanol?- a)10
- b)25
- c)100
- d)million
Correct answer is option 'D'. Can you explain this answer?
Phenol is approximately how much times acidic than ethanol?
a)
10
b)
25
c)
100
d)
million
|
|
Upasana Sen answered |
Phenol is a compound that contains a hydroxyl (-OH) group attached to an aromatic ring. Ethanol, on the other hand, is an alcohol that contains a hydroxyl group (-OH) attached to a saturated carbon atom. The presence of the aromatic ring in phenol makes it more acidic compared to ethanol.
Phenol is a stronger acid than ethanol due to the following reasons:
1. Stability of the phenoxide ion:
- The conjugate base of phenol, known as the phenoxide ion, is stabilized by resonance delocalization.
- The negative charge on the oxygen atom in the phenoxide ion can be delocalized throughout the aromatic ring, making it more stable.
- This resonance stabilization contributes to the acidity of phenol.
2. Inductive effect:
- The presence of the aromatic ring in phenol increases the electron density on the oxygen atom of the hydroxyl group.
- This increased electron density makes the oxygen atom more electronegative and facilitates the release of the hydrogen ion (H+), making phenol more acidic.
3. Effect of aromaticity:
- Aromatic compounds, such as phenol, have a higher degree of stability compared to non-aromatic compounds.
- This stability is due to the delocalization of pi electrons in the aromatic ring, which provides additional stability to the phenol molecule.
- The presence of an aromatic ring in phenol contributes to its increased acidity compared to ethanol.
Based on these factors, phenol is approximately a million times more acidic than ethanol. The resonance stabilization of the phenoxide ion, the inductive effect, and the effect of aromaticity all contribute to the enhanced acidity of phenol.
Phenol is a stronger acid than ethanol due to the following reasons:
1. Stability of the phenoxide ion:
- The conjugate base of phenol, known as the phenoxide ion, is stabilized by resonance delocalization.
- The negative charge on the oxygen atom in the phenoxide ion can be delocalized throughout the aromatic ring, making it more stable.
- This resonance stabilization contributes to the acidity of phenol.
2. Inductive effect:
- The presence of the aromatic ring in phenol increases the electron density on the oxygen atom of the hydroxyl group.
- This increased electron density makes the oxygen atom more electronegative and facilitates the release of the hydrogen ion (H+), making phenol more acidic.
3. Effect of aromaticity:
- Aromatic compounds, such as phenol, have a higher degree of stability compared to non-aromatic compounds.
- This stability is due to the delocalization of pi electrons in the aromatic ring, which provides additional stability to the phenol molecule.
- The presence of an aromatic ring in phenol contributes to its increased acidity compared to ethanol.
Based on these factors, phenol is approximately a million times more acidic than ethanol. The resonance stabilization of the phenoxide ion, the inductive effect, and the effect of aromaticity all contribute to the enhanced acidity of phenol.
What time does it take for reactants to reduce to 3/4 of initial concentration if the rate constant is 7.5 x 10-3 s-1?- a)38.4s
- b)40.2s
- c)39.3s
- d)36.8s
Correct answer is option 'A'. Can you explain this answer?
What time does it take for reactants to reduce to 3/4 of initial concentration if the rate constant is 7.5 x 10-3 s-1?
a)
38.4s
b)
40.2s
c)
39.3s
d)
36.8s
|
|
Abhijeet Sharma answered |
Given:
Rate constant (k) = 7.5 x 10^-3 s^-1
Fractional concentration (f) = 3/4
Time taken for the reaction to occur (t) = ?
We know that the rate law for a first-order reaction can be written as:
Rate = k[A]
Where k is the rate constant and [A] is the concentration of the reactant.
Using the integrated rate law for a first-order reaction, we can write:
ln([A]/[A]0) = -kt
Where [A]0 is the initial concentration of reactant and [A] is the concentration of reactant at time t.
We can rearrange this equation to solve for t:
t = ln([A]0/[A])/k
We are given that the fractional concentration of reactant remaining is 3/4, which means that [A]/[A]0 = 3/4. Substituting this value and the given rate constant into the equation above, we get:
t = ln(4/3)/(7.5 x 10^-3)
Solving this equation gives us t = 38.4 seconds, which is option A.
Rate constant (k) = 7.5 x 10^-3 s^-1
Fractional concentration (f) = 3/4
Time taken for the reaction to occur (t) = ?
We know that the rate law for a first-order reaction can be written as:
Rate = k[A]
Where k is the rate constant and [A] is the concentration of the reactant.
Using the integrated rate law for a first-order reaction, we can write:
ln([A]/[A]0) = -kt
Where [A]0 is the initial concentration of reactant and [A] is the concentration of reactant at time t.
We can rearrange this equation to solve for t:
t = ln([A]0/[A])/k
We are given that the fractional concentration of reactant remaining is 3/4, which means that [A]/[A]0 = 3/4. Substituting this value and the given rate constant into the equation above, we get:
t = ln(4/3)/(7.5 x 10^-3)
Solving this equation gives us t = 38.4 seconds, which is option A.
Which of the following is the correct expression for the temperature coefficient (n)?- a)n = Rate constant at T + 10°/Rate constant at T°
- b)n = Rate constant at T + 20°/Rate constant at T°
- c)n = Rate constant at T + 30°/Rate constant at T°
- d)n = Rate constant at T + 40°/Rate constant at T°
Correct answer is option 'A'. Can you explain this answer?
Which of the following is the correct expression for the temperature coefficient (n)?
a)
n = Rate constant at T + 10°/Rate constant at T°
b)
n = Rate constant at T + 20°/Rate constant at T°
c)
n = Rate constant at T + 30°/Rate constant at T°
d)
n = Rate constant at T + 40°/Rate constant at T°
|
|
Aravind Rane answered |
A) n = Rate constant at T₁ / Rate constant at T₂
The rate constant of a reaction is k=3.28 × 10-4 s-1. Find the order of the reaction.- a)Zero order
- b)First order
- c)Second order
- d)Third order
Correct answer is option 'B'. Can you explain this answer?
The rate constant of a reaction is k=3.28 × 10-4 s-1. Find the order of the reaction.
a)
Zero order
b)
First order
c)
Second order
d)
Third order
|
|
Neha Sharma answered |
Given,
k = 3.28 × 10-4 s-1
The general formula to find the units for rate constant, k = (mol L-1)1-ns-1 where n is the order of the reaction. The value of n must be 1 for (mol L-1)1-ns-1 to become s-1.
Therefore,k = 3.28 × 10-4s-1 represents a first order reaction.
k = 3.28 × 10-4 s-1
The general formula to find the units for rate constant, k = (mol L-1)1-ns-1 where n is the order of the reaction. The value of n must be 1 for (mol L-1)1-ns-1 to become s-1.
Therefore,k = 3.28 × 10-4s-1 represents a first order reaction.
Which of the following is not a property of lanthanides?- a)They are soft metals with white silvery color
- b)They tarnish rapidly by air
- c)The hardness of the metals increases with increase in the atomic number
- d)The melting point of the metal ranges from 500-1000K
Correct answer is option 'D'. Can you explain this answer?
Which of the following is not a property of lanthanides?
a)
They are soft metals with white silvery color
b)
They tarnish rapidly by air
c)
The hardness of the metals increases with increase in the atomic number
d)
The melting point of the metal ranges from 500-1000K
|
|
Tanuja Kapoor answered |
All lanthanides are soft metals with silvery white color. They tarnish rapidly by air. With increase in atomic number, the harness of these metals also increases. The melting points of the lanthanides ranges from 1000 to 1200K but samarium melts at 1623K.
Which of the following is not a consequence of lanthanide contraction?- a)From La+3 to Lu+3, the ionic radii changes from 106 pm to 85 pm
- b)As the size of the lanthanide ions decreases the basic strength increases
- c)The basic character of oxides and hydroxides decreases with increase in atomic number
- d)The atomic radii of 4d and 5d series is similar
Correct answer is option 'B'. Can you explain this answer?
Which of the following is not a consequence of lanthanide contraction?
a)
From La+3 to Lu+3, the ionic radii changes from 106 pm to 85 pm
b)
As the size of the lanthanide ions decreases the basic strength increases
c)
The basic character of oxides and hydroxides decreases with increase in atomic number
d)
The atomic radii of 4d and 5d series is similar
|
|
Aravind Rane answered |
Explanation:
Lanthanide contraction is a phenomenon in which there is a gradual decrease in the size of the lanthanide ions as we move from La to Lu. This phenomenon is caused due to the ineffective shielding of the 4f electrons by the 5s and 5p electrons. The 4f electrons are pulled closer to the nucleus due to the increasing nuclear charge resulting in the contraction of the 4f orbitals. The consequences of the lanthanide contraction are:
a) Change in ionic radii: As we move from La to Lu, the ionic radii of the lanthanide ions decrease gradually from 106 pm to 85 pm.
b) Change in the size of 4d and 5d elements: Due to the lanthanide contraction, the size of 4d and 5d elements becomes almost similar.
c) Decrease in the basic character of oxides and hydroxides: Due to the lanthanide contraction, the size of the lanthanide ions decreases resulting in a decrease in the basic character of oxides and hydroxides.
d) No effect on the basic strength: The basic strength of the lanthanide ions increases with the decrease in size due to the lanthanide contraction.
Therefore, option B is not a consequence of lanthanide contraction. As we move from La to Lu, the size of the lanthanide ions decreases resulting in an increase in the effective nuclear charge. This results in a decrease in the basic strength of the lanthanide ions.
Lanthanide contraction is a phenomenon in which there is a gradual decrease in the size of the lanthanide ions as we move from La to Lu. This phenomenon is caused due to the ineffective shielding of the 4f electrons by the 5s and 5p electrons. The 4f electrons are pulled closer to the nucleus due to the increasing nuclear charge resulting in the contraction of the 4f orbitals. The consequences of the lanthanide contraction are:
a) Change in ionic radii: As we move from La to Lu, the ionic radii of the lanthanide ions decrease gradually from 106 pm to 85 pm.
b) Change in the size of 4d and 5d elements: Due to the lanthanide contraction, the size of 4d and 5d elements becomes almost similar.
c) Decrease in the basic character of oxides and hydroxides: Due to the lanthanide contraction, the size of the lanthanide ions decreases resulting in a decrease in the basic character of oxides and hydroxides.
d) No effect on the basic strength: The basic strength of the lanthanide ions increases with the decrease in size due to the lanthanide contraction.
Therefore, option B is not a consequence of lanthanide contraction. As we move from La to Lu, the size of the lanthanide ions decreases resulting in an increase in the effective nuclear charge. This results in a decrease in the basic strength of the lanthanide ions.
Benzoic ethanoic anhydride on hydrolysis gives _______- a)benzoic acid and methanoic acid
- b)benzoic acid and ethanoic acid
- c)phenylethanoic acid and methanoic acid
- d)no products
Correct answer is option 'B'. Can you explain this answer?
Benzoic ethanoic anhydride on hydrolysis gives _______
a)
benzoic acid and methanoic acid
b)
benzoic acid and ethanoic acid
c)
phenylethanoic acid and methanoic acid
d)
no products
|
Sahil Menon answered |
Hydrolysis of Benzoic Ethanoic Anhydride
Benzoic ethanoic anhydride, also known as ethyl benzoate, is a compound that can undergo hydrolysis in the presence of water. Hydrolysis is a chemical reaction that involves the breaking of a compound by the addition of water molecules. In the case of benzoic ethanoic anhydride, hydrolysis leads to the formation of two products.
Formation of Benzoic Acid
Upon hydrolysis, one of the products formed is benzoic acid. This can be explained by the reaction between the anhydride and water. The water molecule adds to the carbonyl carbon of the anhydride, resulting in the formation of a tetrahedral intermediate. This intermediate then decomposes, leading to the formation of benzoic acid.
Formation of Ethanoic Acid
The other product formed during the hydrolysis of benzoic ethanoic anhydride is ethanoic acid. This can be explained by the reaction between the anhydride and water. The water molecule adds to the carbonyl carbon of the anhydride, resulting in the formation of a tetrahedral intermediate. This intermediate then decomposes, leading to the formation of ethanoic acid.
Overall Reaction
The overall reaction can be represented as follows:
Benzoic Ethanoic Anhydride + H2O → Benzoic Acid + Ethanoic Acid
Conclusion
Upon hydrolysis, benzoic ethanoic anhydride yields benzoic acid and ethanoic acid as the products. This is because the reaction between the anhydride and water leads to the formation of a tetrahedral intermediate, which then decomposes to form the respective carboxylic acids.
Benzoic ethanoic anhydride, also known as ethyl benzoate, is a compound that can undergo hydrolysis in the presence of water. Hydrolysis is a chemical reaction that involves the breaking of a compound by the addition of water molecules. In the case of benzoic ethanoic anhydride, hydrolysis leads to the formation of two products.
Formation of Benzoic Acid
Upon hydrolysis, one of the products formed is benzoic acid. This can be explained by the reaction between the anhydride and water. The water molecule adds to the carbonyl carbon of the anhydride, resulting in the formation of a tetrahedral intermediate. This intermediate then decomposes, leading to the formation of benzoic acid.
Formation of Ethanoic Acid
The other product formed during the hydrolysis of benzoic ethanoic anhydride is ethanoic acid. This can be explained by the reaction between the anhydride and water. The water molecule adds to the carbonyl carbon of the anhydride, resulting in the formation of a tetrahedral intermediate. This intermediate then decomposes, leading to the formation of ethanoic acid.
Overall Reaction
The overall reaction can be represented as follows:
Benzoic Ethanoic Anhydride + H2O → Benzoic Acid + Ethanoic Acid
Conclusion
Upon hydrolysis, benzoic ethanoic anhydride yields benzoic acid and ethanoic acid as the products. This is because the reaction between the anhydride and water leads to the formation of a tetrahedral intermediate, which then decomposes to form the respective carboxylic acids.
If Pt in PtCl4.2HCl has a secondary valence of 6, how many mols of AgCl will 1 mol of the compound precipitate with excess AgNO3?- a)0
- b)1
- c)2
- d)4
Correct answer is option 'A'. Can you explain this answer?
If Pt in PtCl4.2HCl has a secondary valence of 6, how many mols of AgCl will 1 mol of the compound precipitate with excess AgNO3?
a)
0
b)
1
c)
2
d)
4
|
|
Ashwin Iyer answered |
Given: Pt in PtCl4.2HCl has a secondary valence of 6
To find: How many mols of AgCl will 1 mol of the compound precipitate with excess AgNO3?
Solution:
1 mol of PtCl4.2HCl contains 1 mol of Pt.
Since Pt has a secondary valence of 6, it can displace 6 equivalents of Ag+.
Pt + 6Ag+ → Pt+6 + 6Ag
Therefore, 1 mol of PtCl4.2HCl will precipitate 6 mols of AgCl.
But, the question mentions "excess AgNO3".
This means that there is an excess of Ag+ ions present which can react with the Cl- ions from HCl and PtCl4.
Ag+ + Cl- → AgCl
Since the amount of Ag+ ions is in excess, all the Cl- ions will react with Ag+ and form AgCl.
Therefore, no AgCl will be precipitated by PtCl4.2HCl.
Hence, the correct option is A) 0.
To find: How many mols of AgCl will 1 mol of the compound precipitate with excess AgNO3?
Solution:
1 mol of PtCl4.2HCl contains 1 mol of Pt.
Since Pt has a secondary valence of 6, it can displace 6 equivalents of Ag+.
Pt + 6Ag+ → Pt+6 + 6Ag
Therefore, 1 mol of PtCl4.2HCl will precipitate 6 mols of AgCl.
But, the question mentions "excess AgNO3".
This means that there is an excess of Ag+ ions present which can react with the Cl- ions from HCl and PtCl4.
Ag+ + Cl- → AgCl
Since the amount of Ag+ ions is in excess, all the Cl- ions will react with Ag+ and form AgCl.
Therefore, no AgCl will be precipitated by PtCl4.2HCl.
Hence, the correct option is A) 0.
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