Carbon And Its Compounds - Class 10 Science (Compulsory Test) - Class 10 MCQ

To determine the number of covalent bonds in ethane (C₂H₆), we need to count the total number of valence electrons in the molecule.
Step 1: Determine the number of valence electrons for each atom in the molecule.
- Carbon (C) has 4 valence electrons.
- Hydrogen (H) has 1 valence electron.
Step 2: Calculate the total number of valence electrons in the molecule.
- Carbon (C₂) has 2 atoms, so the total number of valence electrons for carbon is 2 x 4 = 8.
- Hydrogen (H₆) has 6 atoms, so the total number of valence electrons for hydrogen is 6 x 1 = 6.
Therefore, the total number of valence electrons in ethane is 8 + 6 = 14.
Step 3: Determine the maximum number of covalent bonds that can be formed by the atoms in the molecule.
- Carbon (C) can form 4 covalent bonds.
- Hydrogen (H) can form 1 covalent bond.
The maximum number of covalent bonds that can be formed by the atoms in ethane is 2 x 4 + 6 x 1 = 14.
Step 4: Divide the total number of valence electrons by 2 to determine the actual number of covalent bonds present in the molecule.
- 14 / 2 = 7.
Therefore, ethane (C₂H₆) has 7 covalent bonds.
Answer: B. 7 covalent bonds.

The compound butanone is a four-carbon compound with the functional group:
- The functional group of butanone is determined by the presence of a carbonyl group (C=O) in its structure.
- The carbonyl group is a carbon atom double-bonded to an oxygen atom.
- Based on the structure of butanone, it can be identified as a ketone.
- Ketones are organic compounds that have a carbonyl group bonded to two other carbon atoms.
- In butanone, the carbonyl group is bonded to two carbon atoms, which makes it a ketone.
- Ketones are named by replacing the "-e" ending of the corresponding alkane with "-one".
- Butanone is derived from the alkane butane, so it is named as butanone.
Therefore, the correct answer is C: ketone.

Explanation:
Reason for the blackening of the vessel:
- When the bottom of the vessel gets blackened on the outside while cooking, it indicates that the fuel is not burning completely.
Causes of incomplete fuel combustion:
- Incomplete combustion of fuel can occur due to various reasons, such as:
- Insufficient supply of oxygen: If there is not enough air or ventilation in the cooking area, the fuel may not burn completely.
- Poor quality of fuel: Low-quality or damp fuel can lead to incomplete combustion.
- Incorrect adjustment of the burner: If the burner is not properly adjusted, it may result in inefficient burning of fuel.
Effects of incomplete fuel combustion:
- Incomplete combustion produces soot, which can accumulate on the bottom of the vessel, causing it to blacken.
- This blackening not only affects the appearance of the vessel but can also lead to poor heat transfer, resulting in uneven cooking.
Prevention and solution:
- To prevent the blackening of the vessel, it is important to ensure complete combustion of the fuel. Here are some steps to achieve this:
- Use good quality and dry fuel.
- Maintain proper ventilation in the cooking area.
- Adjust the burner properly to ensure efficient burning.
- Clean the burner and surrounding area regularly to remove any soot or residue.
Conclusion:
- If the bottom of the vessel is getting blackened on the outside while cooking, it indicates that the fuel is not burning completely. Proper ventilation, high-quality fuel, and correct burner adjustment are essential to achieve complete combustion and prevent blackening of the vessel.

Covalent bonds are formed when atoms share electrons. Here is a detailed explanation of how covalent bonds are formed:
1. Definition of covalent bond:
A covalent bond is a chemical bond formed between atoms when they share one or more pairs of electrons. It is a type of bonding that occurs between nonmetallic elements.
2. Mutual sharing of electrons:
In a covalent bond, electrons are shared between atoms rather than being transferred completely. This sharing of electrons allows both atoms to achieve a more stable electron configuration, similar to the noble gases.
3. Equal sharing of electrons:
Covalent bonds can be classified into two types based on the sharing of electrons:
- Nonpolar covalent bond: In a nonpolar covalent bond, the electrons are shared equally between the atoms involved. This occurs when the electronegativity (the ability of an atom to attract electrons) of both atoms is similar or equal.
- Polar covalent bond: In a polar covalent bond, the electrons are not shared equally between the atoms involved. This occurs when there is a difference in electronegativity between the atoms. The atom with higher electronegativity attracts the shared electrons more strongly, resulting in a partial positive charge on one atom and a partial negative charge on the other.
4. Formation of a covalent bond:
The formation of a covalent bond involves the following steps:
- Two atoms approach each other and their electron orbitals overlap.
- The overlapping orbitals create a region of electron density between the two atoms, known as a bonding orbital.
- The shared electrons occupy the bonding orbital, creating a stable electron configuration for both atoms.
- The strength of the covalent bond depends on factors such as the number of shared electrons and the distance between the nuclei of the atoms involved.
5. Examples of covalent compounds:
- Water (H2O): Oxygen and hydrogen share electrons to form covalent bonds.
- Methane (CH4): Carbon and hydrogen share electrons to form covalent bonds.
- Carbon dioxide (CO2): Carbon and oxygen share electrons to form covalent bonds.
In conclusion, a covalent bond is formed through the mutual sharing of electrons between atoms. This sharing allows each atom to achieve a more stable electron configuration and results in the formation of covalent compounds.

To determine which compound does not contain a multiple bond, we need to understand the concept of multiple bonds and identify the compounds that do or do not have them.
A multiple bond is a covalent bond in which two or more pairs of electrons are shared between two atoms. It consists of a sigma bond, which is the first bond formed by the overlap of atomic orbitals, and one or more pi bonds, which are formed by the sideways overlap of atomic p orbitals.
Let's analyze each compound and determine if it contains a multiple bond:
A: Ethane
- Ethane (C2H6) consists of two carbon atoms bonded together by a single sigma bond. It also has hydrogen atoms attached to each carbon atom.
- Ethane does not contain a multiple bond.
B: Ethene
- Ethene (C2H4) consists of two carbon atoms bonded together by a double bond, which consists of one sigma bond and one pi bond. It also has hydrogen atoms attached to each carbon atom.
- Ethene contains a multiple bond.
C: Ethyne
- Ethyne (C2H2) consists of two carbon atoms bonded together by a triple bond, which consists of one sigma bond and two pi bonds. It also has hydrogen atoms attached to each carbon atom.
- Ethyne contains a multiple bond.
D: Benzene
- Benzene (C6H6) consists of a ring of six carbon atoms bonded together by alternating single and double bonds. It has three double bonds, each consisting of one sigma bond and one pi bond. It also has hydrogen atoms attached to each carbon atom.
- Benzene contains multiple bonds.
Therefore, the compound that does not contain a multiple bond is A: Ethane.

To determine which of the given options is not a saturated hydrocarbon, we need to understand the characteristics of a saturated hydrocarbon and examine each option.
Saturated Hydrocarbon:
A saturated hydrocarbon is a hydrocarbon molecule that contains only single bonds between carbon atoms. Each carbon atom in a saturated hydrocarbon is bonded to the maximum number of hydrogen atoms. Saturated hydrocarbons are also known as alkanes.
Now, let's examine each option to determine which one is not a saturated hydrocarbon:
A: Cyclohexane:
- Cyclohexane is a saturated hydrocarbon.
- Its chemical formula is C6H12.
- It contains only single bonds between carbon atoms.
B: Benzene:
- Benzene is not a saturated hydrocarbon.
- Its chemical formula is C6H6.
- It contains alternating double bonds between carbon atoms, which makes it unsaturated.
C: Butane:
- Butane is a saturated hydrocarbon.
- Its chemical formula is C4H10.
- It contains only single bonds between carbon atoms.
D: Isobutane:
- Isobutane is a saturated hydrocarbon.
- Its chemical formula is C4H10.
- It contains only single bonds between carbon atoms.
Answer:
The option that is not a saturated hydrocarbon is B: Benzene.

To determine the number of single and double bonds in benzene (C₆H₆), let's analyze its structure.
1. Structure of benzene:
- Benzene consists of a ring of six carbon atoms, with one hydrogen atom attached to each carbon atom.
- The carbon atoms are arranged in a hexagonal shape, with alternating single and double bonds between them.
2. Bonding in benzene:
- Each carbon atom in benzene forms three sigma (σ) bonds and one pi (π) bond.
- The sigma bonds are formed by overlapping of sp² hybrid orbitals of carbon atoms with the 1s orbital of the hydrogen atom.
- The pi bond is formed by the sideways overlap of p orbitals on adjacent carbon atoms.
3. Counting the bonds:
- Each carbon atom in benzene forms one sigma bond with each of its two adjacent carbon atoms, totaling six sigma bonds.
- In addition, there are three pi bonds distributed around the ring, formed by the overlap of p orbitals.
- Therefore, benzene has a total of nine single bonds (sigma bonds) and three double bonds (pi bonds).
Therefore, the correct answer is B: 9 single bonds and 3 double bonds.

Functional Groups in Methanol and Methanal:
Methanol and methanal are both organic compounds, and they have different functional groups. The functional groups in methanol and methanal respectively are:
1. Methanol:
- Methanol is also known as methyl alcohol or wood alcohol.
- The chemical formula of methanol is CH3OH.
- The functional group present in methanol is -OH, which is the hydroxyl group.
- The -OH group is attached to the carbon atom, making methanol a primary alcohol.
- The hydroxyl group (-OH) gives methanol its characteristic properties, such as its ability to form hydrogen bonds and its solubility in water.
2. Methanal:
- Methanal is also known as formaldehyde or formalin.
- The chemical formula of methanal is HCHO.
- The functional group present in methanal is -CHO, which is the aldehyde group.
- The aldehyde group (-CHO) is a carbonyl group, consisting of a carbon atom double-bonded to an oxygen atom and single-bonded to a hydrogen atom.
- The aldehyde group gives methanal its characteristic properties, such as its ability to undergo oxidation and reduction reactions.
Therefore, the functional groups in methanol and methanal respectively are -OH and -CHO. Hence, the correct answer is A: -OH, -CHO.

To determine which of the given options is not an allotropic form of carbon, we need to understand the concept of allotropes of carbon and analyze each option.
Allotropes of Carbon:
Allotropes are different forms of an element that exist in the same physical state but have different chemical properties. Carbon is known to have several allotropes, some of which include:
1. Coal:
Coal is a sedimentary rock primarily composed of carbon along with various impurities. It is not considered an allotropic form of carbon because it is a rock rather than a distinct form of the element.
2. Fullerene:
Fullerenes are a class of allotropes of carbon that consist of carbon atoms arranged in closed cage-like structures. They can have different shapes, such as spherical (buckyballs) or cylindrical (nanotubes). Fullerene is a valid allotropic form of carbon.
3. Diamond:
Diamond is a well-known allotrope of carbon that forms a crystal lattice structure. It consists of carbon atoms arranged in a tetrahedral fashion, resulting in a hard and transparent material. Diamond is a valid allotropic form of carbon.
4. Graphite:
Graphite is another common allotrope of carbon that consists of layers of carbon atoms arranged in a hexagonal lattice. It has a layered structure and is known for its slippery and opaque properties. Graphite is a valid allotropic form of carbon.
Conclusion:
Based on the explanation above, the correct answer is A: Coal. Coal is not an allotropic form of carbon as it is a sedimentary rock composed of carbon and other impurities, whereas fullerene, diamond, and graphite are distinct forms of carbon with unique structures and properties.

Graphite is a soft lubricant extremely difficult to melt. The reason for this anomalous behaviour is that graphite:
- Has carbon atoms arranged in large plates of rings of strongly bound carbon atoms with weak interplate bonds: This is the correct answer. Graphite is made up of layers of carbon atoms arranged in a hexagonal lattice. Within each layer, the carbon atoms are strongly bonded in a planar structure. However, the layers are held together by weak van der Waals forces, allowing them to easily slide over each other, giving graphite its lubricating properties. The weak interplate bonds also make it difficult to melt graphite since high temperatures are required to break these bonds.
- Is a non-crystalline substance: This statement is incorrect. Graphite is a crystalline substance with a well-defined atomic structure.
- Is an allotropic form of carbon: This statement is correct. Graphite is one of the allotropic forms of carbon, along with diamond, amorphous carbon, and fullerenes. Allotropic forms refer to different structures or arrangements of the same element.
- Has only single bonds between carbon atoms: This statement is incorrect. Graphite is composed of carbon atoms that are bonded together in a hexagonal lattice, with each carbon atom forming three sigma bonds and one pi bond. The presence of pi bonds contributes to the delocalized electrons in graphite, which give it its unique electrical conductivity.
In conclusion, the correct reason for graphite's anomalous behavior is that it has carbon atoms arranged in large plates of rings of strongly bound carbon atoms with weak interplate bonds.

Alkanes are saturated hydrocarbons. Alkenes and alkynes are unsaturated hydrocarbons. So, increasing order of unsaturation is Alkanes, Alkenes and Alkynes.

Answer:
To denature ethanol, a substance is added to make it unfit for consumption. The most common substance used for denaturing ethanol is methanol. Here is a detailed explanation:
Denaturing Ethanol:
Denaturing ethanol involves adding a substance to make it toxic or unpalatable, thus rendering it unsuitable for consumption. This process is done to prevent the misuse or illegal consumption of ethanol.
Substances Used for Denaturing Ethanol:
There are various substances that can be used to denature ethanol. However, methanol is the most commonly used substance due to its effectiveness and low cost. Methanol is a toxic alcohol that can cause severe health problems if ingested.
Reasons for Using Methanol:
Methanol is added to ethanol for denaturation because:
1. Toxicity: Methanol is highly toxic when ingested, causing metabolic acidosis and potential damage to the optic nerve, leading to blindness or even death.
2. Availability: Methanol is readily available and relatively inexpensive, making it a cost-effective option for denaturing ethanol.
3. Effectiveness: Methanol effectively renders ethanol undrinkable due to its toxic nature.
It is important to note that the addition of methanol or any other denaturing agent must follow specific regulations and guidelines to ensure the safety and effectiveness of the denatured ethanol product.

Explanation:
Detergents are commonly used for cleaning purposes. They are composed of long-chain molecules that have both hydrophilic (water-loving) and hydrophobic (water-repelling) properties. The hydrophilic part allows the detergent to dissolve in water, while the hydrophobic part allows it to interact with and remove dirt and grease.
The salts used in detergents are usually sodium or potassium salts. These salts contribute to the overall stability and solubility of the detergent. Sodium and potassium ions are commonly found in detergents because they are readily available and have good solubility in water.
The long-chain molecules in detergents are typically derived from sulfonic acids. Sulfonic acids are organic compounds that contain a sulfonic group (-SO3H). These acids are then neutralized with sodium or potassium hydroxide to form the corresponding salts.
In summary, detergents are sodium or potassium salts of long-chain sulfonic acids. These salts provide the necessary solubility and stability for the detergent to effectively clean various surfaces.
Key Points:
- Detergents are composed of long-chain molecules with hydrophilic and hydrophobic properties.
- The salts used in detergents are usually sodium or potassium salts.
- Long-chain sulfonic acids are commonly used in detergents.
- The sulfonic acids are neutralized with sodium or potassium hydroxide to form the salts.
- The salts provide solubility and stability to the detergent.

Explanation:

Hard water is water that contains a high concentration of dissolved minerals, particularly calcium and magnesium ions.

Salts that produce hard water:

• Calcium sulphate: When dissolved in water, calcium sulphate dissociates into calcium ions (Ca2+) and sulphate ions (SO42-), contributing to the hardness of water.


• Magnesium bicarbonate: When dissolved in water, magnesium bicarbonate dissociates into magnesium ions (Mg2+) and bicarbonate ions (HCO3-). The presence of magnesium ions contributes to water hardness.


• Calcium chloride: When dissolved in water, calcium chloride dissociates into calcium ions (Ca2+) and chloride ions (Cl-), both of which contribute to water hardness.

Conclusion:

All of the above salts, namely calcium sulphate, magnesium bicarbonate, and calcium chloride, when dissolved in water, produce hard water. Therefore, the correct answer is D: Any of the above salts.

To determine which compound will not decolourise bromine water, we need to understand the reaction between bromine water and different compounds. Bromine water is a solution of bromine (Br2) dissolved in water, and it acts as an oxidizing agent. It can decolourise substances that can be oxidized by bromine.
Let's analyze each compound and its reaction with bromine water:
A: C₄H₈
- This compound contains a double bond, which is a site of unsaturation. Bromine water can add across the double bond, causing the bromine to be reduced and the compound to be oxidized. It will decolourise bromine water.
B: C₃H₄
- This compound also contains a double bond. Similar to compound A, it can undergo addition reaction with bromine water and decolourise it.
C: C₃H₈
- This compound is propane, an alkane. Alkanes are saturated hydrocarbons and do not contain any double or triple bonds. Bromine water does not react with alkanes, so it will not decolourise bromine water.
D: C₄H₆
- This compound contains a triple bond. Triple bonds are reactive and can undergo addition reactions with bromine water. It will decolourise the bromine water.
Therefore, the compound that will not decolourise bromine water is C: C₃H₈.

Explanation:
Compounds made up of carbon and hydrogen only are called hydrocarbons. Hydrocarbons are organic compounds that consist entirely of carbon and hydrogen atoms. They are the simplest and most abundant class of organic compounds.
The different types of hydrocarbons include:
- Alkanes: Alkanes are saturated hydrocarbons with single bonds between carbon atoms. They have the general formula CnH2n+2. Examples of alkanes include methane (CH4), ethane (C2H6), and propane (C3H8).
- Alkenes: Alkenes are unsaturated hydrocarbons with at least one double bond between carbon atoms. They have the general formula CnH2n. Examples of alkenes include ethene (C2H4), propene (C3H6), and butene (C4H8).
- Alkynes: Alkynes are unsaturated hydrocarbons with at least one triple bond between carbon atoms. They have the general formula CnH2n-2. Examples of alkynes include ethyne (C2H2), propyne (C3H4), and butyne (C4H6).
Therefore, the correct answer is D: Hydrocarbons.

The mentioned reaction shows the acidic nature of ethanol as acidic donates protons which on reduction forms hydrogen gas. Here Na i.e. sodium is a metal and is basic in nature.  Sodium being strong base force ethanol to act as an acid and hence produces hydrogen gas. 

The characteristic reaction of alkanes is substitution.
Explanation:
The reaction of alkanes, which are saturated hydrocarbons, is primarily characterized by substitution reactions, where one or more hydrogen atoms in the alkane molecule are replaced by other atoms or groups.
Here are the reasons why substitution is the characteristic reaction of alkanes:
1. Carbon-hydrogen bond reactivity: Alkanes have relatively unreactive carbon-hydrogen (C-H) bonds due to the high bond strength. These bonds are difficult to break, making addition reactions less favorable.
2. Radical initiation: Substitution reactions in alkanes are often initiated by free radicals, which are highly reactive species. These radicals can be formed by the homolytic cleavage of a weak bond (such as a halogen-halogen bond) in the presence of heat or light.
3. Halogenation: Halogenation is a common example of substitution reactions in alkanes. In this reaction, a halogen atom (such as chlorine or bromine) replaces a hydrogen atom in the alkane molecule, resulting in the formation of a halogenated alkane.
4. Other substitution reactions: Alkanes can undergo various other substitution reactions, such as nitration, sulfonation, and oxidation, where different atoms or groups replace hydrogen atoms in the alkane molecule.
5. Isomerization and polymerization: While isomerization and polymerization reactions can occur in alkanes, they are not the characteristic reactions of alkanes. Isomerization involves rearranging the atoms within a molecule to form a different isomer, while polymerization involves the combination of monomers to form a polymer.
In conclusion, the characteristic reaction of alkanes is substitution, where one or more hydrogen atoms in the alkane molecule are replaced by other atoms or groups.

The major constituent of biogas is methane.

• Methane is the primary component of biogas, typically making up around 50-70% of its composition.


• Biogas is produced through the anaerobic digestion of organic matter, such as animal manure, sewage sludge, or agricultural waste.


• During the anaerobic digestion process, microorganisms break down the organic matter and produce biogas as a byproduct.


• In addition to methane, biogas also contains smaller amounts of carbon dioxide (CO2), nitrogen (N2), hydrogen (H2), and traces of other gases.


• The methane in biogas is a potent greenhouse gas, and its capture and utilization as a renewable energy source can help mitigate climate change.


• Biogas can be used for various purposes, including electricity generation, heating, and cooking.


• It is considered a renewable energy source because it is produced from organic materials that can be replenished.

Explanation:
Isobutane and n-butane are both hydrocarbons, meaning they consist only of carbon and hydrogen atoms. However, they differ in their structural arrangement, making them isomers of each other.
Isomers:
Isomers are compounds that have the same molecular formula but different structural arrangements or spatial orientations. In the case of isobutane and n-butane:
- Isobutane: Isobutane is an isomer of butane. It has a branched structure with one methyl group (CH3) attached to the second carbon atom of the main carbon chain. Its molecular formula is C4H10.
- n-Butane: n-Butane, also known as normal butane, has a straight or linear structure with four carbon atoms in a row. Its molecular formula is also C4H10.
Therefore, isobutane and n-butane are considered isomers because they have the same molecular formula (C4H10) but different structural arrangements.
Conclusion:
The correct answer is C: Isomers.

The general formula of alcohol is:
Answer: B. C_nH_{2n 1}OH
Explanation:
Alcohols are a class of organic compounds that contain a hydroxyl (-OH) group attached to a carbon atom. The general formula for alcohol can be represented as C_nH_{2n 1}OH, where "n" represents the number of carbon atoms in the alcohol molecule.
To understand why the answer is B, let's break down the formula:
- C_n: This represents the number of carbon atoms in the alcohol molecule. The letter "C" stands for carbon, and "n" represents the number of carbon atoms. For example, if the alcohol molecule has 2 carbon atoms, it would be represented as C₂.
- H_{2n 1}: This represents the number of hydrogen atoms in the alcohol molecule. The letter "H" stands for hydrogen, and "2n 1" means that there are twice as many hydrogen atoms as there are carbon atoms, plus an additional hydrogen atom. For example, if the alcohol molecule has 2 carbon atoms, there would be 5 hydrogen atoms (2 x 2 + 1 = 5).
- OH: This represents the hydroxyl group, which consists of an oxygen atom (O) bonded to a hydrogen atom (H). It is always present in alcohols.
Therefore, the general formula of alcohol is C_nH_{2n 1}OH, where "n" represents the number of carbon atoms in the alcohol molecule.

Explanation:
The acid present in vinegar is acetic acid, which has the chemical formula CH₃COOH. Here is a detailed explanation:
Acetic Acid:
- Acetic acid is a weak acid that is commonly found in vinegar.
- Its chemical formula is CH₃COOH.
- It is a colorless liquid with a strong, pungent smell.
- Acetic acid is produced through the fermentation process of ethanol by acetic acid bacteria.
Vinegar:
- Vinegar is a liquid that is commonly used in cooking and cleaning.
- It is made through the fermentation of ethanol or acetic acid bacteria.
- The main component of vinegar is acetic acid.
Options:
A: CH₃COOH - This is the correct answer as it represents the chemical formula of acetic acid.
B: HCOOH - This represents formic acid, which is not the acid present in vinegar.
C: CH₃CH₂COOH - This represents propanoic acid, which is not the acid present in vinegar.
D: CH₃CH₂CH₂COOH - This represents butanoic acid, which is not the acid present in vinegar.
Conclusion:
The acid present in vinegar is acetic acid, which has the chemical formula CH₃COOH.

Ethanol on oxidation gives

Ethanol, which is a primary alcohol, undergoes oxidation reactions to form various products. The most common product formed during the oxidation of ethanol is ethanoic acid, also known as acetic acid. This reaction occurs in the presence of an oxidizing agent, such as potassium dichromate (K2Cr2O7) or acidified potassium permanganate (KMnO4).

Possible products of ethanol oxidation:

• Ethanoic acid (acetic acid): This is the major product obtained during the oxidation of ethanol. It is a carboxylic acid and is commonly used in vinegar and various industrial processes.


• Formaldehyde (methanal): In some cases, ethanol can be oxidized to formaldehyde, which is a gas with a pungent odor. Formaldehyde is used in various applications, including disinfectants and resins.


• Carbon dioxide (CO2) and water (H2O): Complete oxidation of ethanol can lead to the formation of carbon dioxide and water. This reaction occurs when ethanol is burned in the presence of excess oxygen.


• Other byproducts: Depending on the reaction conditions and the presence of impurities, other byproducts such as acetaldehyde and carbon monoxide may also be formed.

Conclusion:

When ethanol undergoes oxidation, the most common product formed is ethanoic acid (acetic acid). However, depending on the reaction conditions and the presence of impurities, other products such as formaldehyde, carbon dioxide, and water may also be obtained.

Functional Group in Carboxylic Acids:
Carboxylic acids are organic compounds that contain the carboxyl functional group (-COOH). This functional group consists of a carbonyl group (C=O) and a hydroxyl group (-OH) attached to the same carbon atom. The carboxyl group is responsible for the acidic properties of carboxylic acids.
Explanation:
The functional group present in carboxylic acids is the carboxyl group (-COOH), which consists of a carbonyl group (C=O) and a hydroxyl group (-OH) attached to the same carbon atom. This arrangement gives carboxylic acids their unique properties and reactivity. The carbonyl group is a polar functional group, while the hydroxyl group provides acidity to the compound.
Summary:
In summary, the functional group present in carboxylic acids is the carboxyl group (-COOH), which consists of a carbonyl group (C=O) and a hydroxyl group (-OH) attached to the same carbon atom. This functional group is responsible for the acidic properties and reactivity of carboxylic acids.

Answer:
The correct answer is C: Vinegar.
Explanation:
A dilute solution of ethanoic acid in water is commonly known as vinegar. Vinegar is a popular condiment that is used in cooking, food preservation, and cleaning due to its acidic properties. Here are some key points to understand:
1. Ethanoic acid: Ethanoic acid, also known as acetic acid, is a weak acid with the chemical formula CH3COOH. It is formed through the oxidation of ethanol.
2. Dilute solution: Vinegar typically contains about 5-8% acetic acid in water, making it a dilute solution. The concentration can vary depending on the type of vinegar.
3. Properties of vinegar: Vinegar has a sour taste, a pungent odor, and a low pH value. It is known for its antimicrobial properties, making it useful for food preservation and cleaning.
4. Uses of vinegar: Vinegar is widely used in cooking as a flavoring agent, salad dressing, and marinade. It is also used for pickling vegetables, as the acidic environment inhibits the growth of bacteria. Additionally, vinegar can be used as a natural cleaning agent.
In conclusion, a dilute solution of ethanoic acid in water is commonly referred to as vinegar due to its widespread use and familiar name.

Functional Group in Aldehydes:
The functional group in aldehydes is -CHO. This functional group is known as an aldehyde group. It consists of a carbon atom bonded to a hydrogen atom and a double-bonded oxygen atom.
Explanation:
- Aldehydes are a class of organic compounds that contain the aldehyde functional group.
- The aldehyde functional group is represented by the -CHO suffix.
- The carbon atom in the aldehyde group is sp2 hybridized, meaning it forms three sigma bonds and one pi bond.
- The double bond between the carbon and oxygen atoms gives the aldehyde its characteristic reactivity.
- The hydrogen atom attached to the carbon atom can be replaced by other substituents, resulting in different aldehyde compounds.
- Aldehydes are commonly used in various chemical reactions and organic synthesis due to their unique properties and reactivity.
- Examples of aldehydes include formaldehyde (HCHO), acetaldehyde (CH3CHO), and benzaldehyde (C6H5CHO).
In conclusion, the functional group in aldehydes is -CHO, which is a characteristic feature of aldehyde compounds.

Explanation:
To identify the alkyne, we need to understand the structure and properties of alkyne compounds. Alkynes are hydrocarbons that contain a triple bond between two carbon atoms. They are characterized by the general formula CnH2n-2.
Given options:
A: C6H6
B: C6H12
C: C6H10
D: C6H14
Analysis:
We need to determine which of the given compounds has the structure of an alkyne.
Answer:
The correct answer is C: C6H10.
Explanation:
- Compound A (C6H6) is benzene, which is an aromatic compound and does not contain a triple bond. Therefore, it is not an alkyne.
- Compound B (C6H12) is a saturated hydrocarbon, suggesting the presence of only single bonds between carbon atoms. It does not contain a triple bond and is not an alkyne.
- Compound D (C6H14) is a saturated hydrocarbon, similar to compound B, and does not contain a triple bond. It is not an alkyne.
Compound C (C6H10) is the only option left. To determine if it is an alkyne, we can use the general formula for alkynes (CnH2n-2). By substituting n = 6, we get C6H10, which matches the given compound. Therefore, compound C (C6H10) is an alkyne.
To recap:
- Compound A (C6H6) is not an alkyne.
- Compound B (C6H12) is not an alkyne.
- Compound C (C6H10) is an alkyne.
- Compound D (C6H14) is not an alkyne.
Hence, the correct answer is C: C6H10.

Explanation:
The class of organic compounds that give effervescence with NaHCO3 solution is carboxylic acids. This can be explained by the following points:
Effervescence:
Effervescence refers to the release of gas bubbles when a solid or liquid reacts with a solution. In this case, when a carboxylic acid reacts with NaHCO3 solution, it produces carbon dioxide gas (CO2), which leads to effervescence.
Reaction with NaHCO3:
When a carboxylic acid reacts with NaHCO3, it undergoes a neutralization reaction. The reaction can be represented by the following general equation:
RCOOH + NaHCO3 → RCOONa + H2O + CO2
Where R represents the carbon chain of the carboxylic acid.
Formation of Carbon Dioxide:
The formation of carbon dioxide gas is the reason for the effervescence observed. Carbon dioxide is a gas that is released as bubbles when the reaction occurs. This gas is responsible for the fizzing or effervescence that can be observed.
Other Classes of Organic Compounds:
While carboxylic acids give effervescence with NaHCO3, other classes of organic compounds do not exhibit this reaction. Here are some examples:
- Esters: Esters are organic compounds that are derived from carboxylic acids. However, they do not react with NaHCO3 to produce effervescence.
- Alcohols: Alcohols are organic compounds that contain hydroxyl (-OH) functional group. They do not react with NaHCO3 to produce effervescence.
- Aldehydes: Aldehydes are organic compounds that contain a carbonyl group (-CHO). They do not give effervescence with NaHCO3.
Overall, carboxylic acids are the class of organic compounds that give effervescence when reacted with NaHCO3 solution due to the formation of carbon dioxide gas.

Carboxylic acids are obtained from alcohols by oxidation.
Carboxylic acids are organic compounds that contain a carboxyl group (-COOH). They can be obtained from alcohols through a process called oxidation. Here is a detailed explanation of how alcohols are oxidized to produce carboxylic acids:
Oxidation of Alcohols:
1. Alcohols contain an -OH group bonded to a carbon atom.
2. Oxidation involves the loss of electrons from a molecule or atom.
3. In the case of alcohols, the carbon atom bonded to the -OH group undergoes oxidation.
4. The oxidation of alcohols can be carried out using various oxidizing agents, such as potassium permanganate (KMnO4), potassium dichromate (K2Cr2O7), or chromic acid (H2CrO4).
5. The oxidizing agent accepts electrons from the carbon atom, resulting in the formation of a carboxylic acid.
Steps in the Oxidation Process:
1. The alcohol reacts with the oxidizing agent, transferring electrons to the oxidizing agent.
2. The alcohol is oxidized to an aldehyde or a carboxylic acid, depending on the reaction conditions.
3. Further oxidation of the aldehyde can occur to produce a carboxylic acid.
4. The oxidizing agent is reduced in the process, gaining electrons.
Example:
For example, the oxidation of ethanol (C2H5OH) using potassium dichromate (K2Cr2O7) as the oxidizing agent results in the formation of acetic acid (CH3COOH) and chromium(III) oxide (Cr2O3).
C2H5OH + [O] -> CH3COOH + H2O
In this reaction, ethanol is oxidized to acetic acid, and the potassium dichromate is reduced to chromium(III) oxide.
Therefore, the correct answer is A: Oxidation.

Explanation:
To prepare soaps, alkaline hydrolysis is used. Alkaline hydrolysis is a process in which a chemical compound is broken down by reaction with water using an alkaline solution. In the case of soap preparation, alkaline hydrolysis is used to break down higher esters.
Reasoning:
Soaps are typically made from fats and oils, which are esters of fatty acids. The process of making soap involves a reaction called saponification, in which the ester bond in fats and oils is hydrolyzed by an alkaline solution. This hydrolysis breaks down the ester into its constituent parts, a carboxylic acid and an alcohol.
Correct answer:
The correct answer is option C: Higher esters. Soaps are prepared by alkaline hydrolysis of higher esters, which are the esters of fatty acids found in fats and oils.
Key points:
- Soaps are prepared by alkaline hydrolysis.
- Alkaline hydrolysis is a process in which a chemical compound is broken down by reaction with water using an alkaline solution.
- Soaps are made from fats and oils, which are esters of fatty acids.
- The process of making soap involves saponification, which is the hydrolysis of ester bonds in fats and oils.
- Soaps are prepared by the alkaline hydrolysis of higher esters, which are the esters of fatty acids found in fats and oils.