All questions of Adsorption for Chemistry Exam

°C. Calculate the amount of acetic acid adsorbed by 1 kg of charcoal at the same conditions.

To calculate the amount of acetic acid adsorbed by 1 kg of charcoal, we need to convert the given values to the same units.

1 kg of charcoal is equal to 1000 g.

The surface area of 1 g of charcoal is given as 100 m2 per gram.

Therefore, the surface area of 1000 g (1 kg) of charcoal is 1000 * 100 = 100,000 m2.

The amount of acetic acid adsorbed by 1 g of charcoal is given as 60 mg.

To find the amount of acetic acid adsorbed by 1 kg of charcoal, we multiply the amount adsorbed by 1 g by the mass of charcoal:

60 mg/g * 1000 g = 60,000 mg

To convert mg to grams, we divide by 1000:

60,000 mg / 1000 = 60 g

Therefore, 1 kg of charcoal at the same conditions will adsorb 60 g of acetic acid.

Langmuir isotherm is a model that explains the adsorption phenomenon on a solid surface. It is named after Irving Langmuir, who proposed this model in 1916. The true statements about Langmuir isotherm are:

Valid for Monolayer Coverage:
Langmuir isotherm is valid for monolayer coverage, which means that it assumes that only one layer of gas molecules is adsorbed on the surface of the solid. This assumption is valid when the surface of the solid is homogeneous and the adsorption sites are equivalent.

All Adsorption Sites are Equivalent:
Langmuir isotherm assumes that all the adsorption sites on the surface of the solid are equivalent. It means that the probability of adsorption of gas molecules on any adsorption site is the same.

There is Dynamic Equilibrium between Free Gas and Adsorbed Gas:
Langmuir isotherm assumes that there is a dynamic equilibrium between the free gas molecules and the adsorbed gas molecules on the surface of the solid. At equilibrium, the rate of adsorption is equal to the rate of desorption.

Adsorption Probability is Independent of Occupancy at the Neighboring Sites:
Langmuir isotherm assumes that the probability of adsorption of gas molecules on a particular site is independent of the occupancy of the neighboring sites. It means that the adsorption probability is not affected by the presence or absence of adsorbed gas molecules on the neighboring sites.

In conclusion, Langmuir isotherm is a useful model to understand the adsorption phenomenon on a solid surface. It assumes that the adsorption sites are equivalent, there is a dynamic equilibrium between the free gas and the adsorbed gas, the probability of adsorption is independent of the neighboring sites, and it is valid for monolayer coverage.

According to langmuir Adsorption isotherm the amount of gas adsorbed at very high pressures reaches a constant limiting volume.

The adsorption of gases on charcoal is influenced by several factors, including the nature of the gas molecules and the properties of the charcoal surface. In this case, we are given four gases: CO2, SO2, CH4, and H2, and we need to determine which gas shows the least adsorption on a definite amount of charcoal.

To predict the gas with the least adsorption, we can consider the following factors:

1. Molecular Size: The size of the gas molecules can affect their adsorption on the charcoal surface. Smaller molecules can penetrate the pores of the charcoal more easily, leading to stronger adsorption. Larger molecules may have difficulty accessing the charcoal surface and thus show weaker adsorption.

2. Polarity: The polarity of the gas molecules can also affect their adsorption. Polar molecules have dipole moments, which can interact with polar sites on the charcoal surface through dipole-dipole interactions. Nonpolar molecules, on the other hand, do not have dipole moments and may have weaker interactions with the charcoal surface.

Based on these factors, we can analyze the given gases:

a) CO2: Carbon dioxide is a relatively small molecule (linear with a molecular weight of 44 g/mol). It is also a polar molecule due to its linear geometry and the presence of polar carbon-oxygen bonds. CO2 can undergo dipole-dipole interactions with the charcoal surface, leading to moderate adsorption.

b) SO2: Sulfur dioxide is a larger molecule compared to CO2 (bent shape with a molecular weight of 64 g/mol). It is also a polar molecule due to the presence of polar sulfur-oxygen bonds. SO2 can undergo dipole-dipole interactions with the charcoal surface, similar to CO2. However, the larger size of SO2 may limit its access to the charcoal surface, resulting in weaker adsorption compared to CO2.

c) CH4: Methane is the smallest molecule among the given gases (tetrahedral shape with a molecular weight of 16 g/mol). It is a nonpolar molecule as it consists of only carbon-hydrogen bonds. Methane does not have a dipole moment and lacks the ability to form strong dipole-dipole interactions with the charcoal surface. Therefore, methane is expected to show weaker adsorption compared to CO2 and SO2.

d) H2: Hydrogen gas is the smallest molecule among the given gases (diatomic with a molecular weight of 2 g/mol). It is also a nonpolar molecule as it consists of two hydrogen atoms bonded together. Similar to methane, hydrogen gas lacks a dipole moment and strong dipole-dipole interactions with the charcoal surface. Therefore, hydrogen gas is expected to show weaker adsorption compared to CO2 and SO2.

Based on the analysis above, we can conclude that SO2 shows the least adsorption on a definite amount of charcoal among the given gases (CO2, SO2, CH4, and H2).

Protective Power of Lyophilic Colloidal Sol

The protective power of lyophilic colloidal sol refers to its ability to protect colloidal particles from coagulation or aggregation. When a colloidal sol is formed, the particles are dispersed and stabilized in a medium. However, these particles have a tendency to aggregate due to attractive forces between them. The protective power of a lyophilic colloidal sol helps to prevent or minimize this aggregation, thus maintaining the stability of the sol.

Gold Number

The protective power of lyophilic colloidal sol is quantitatively expressed in terms of the Gold Number. The Gold Number is a measure of the amount of an electrolyte required to cause coagulation or aggregation of a given volume of a lyophilic colloidal sol. It is named after Thomas Thomson Gold, who first introduced this concept.

Principle of Gold Number

The principle behind the Gold Number is based on the fact that the addition of an electrolyte to a colloidal sol neutralizes the charge on the colloidal particles. When the charge is neutralized, the repulsive forces between the particles decrease, leading to their aggregation. The Gold Number represents the minimum amount of electrolyte required to cause coagulation under specific conditions.

Determination of Gold Number

To determine the Gold Number, a series of solutions with different concentrations of an electrolyte are prepared. A fixed volume of the colloidal sol is added to each solution, and the mixture is observed for coagulation. The Gold Number is the minimum concentration of the electrolyte that causes coagulation.

Significance of Gold Number

The Gold Number provides a quantitative measure of the protective power of a lyophilic colloidal sol. Higher Gold Numbers indicate greater protective power, as a larger amount of electrolyte is required to cause coagulation. Therefore, a higher Gold Number implies greater stability of the colloidal sol.

Conclusion

In conclusion, the protective power of lyophilic colloidal sol is expressed in terms of the Gold Number. The Gold Number represents the minimum concentration of an electrolyte required to cause coagulation of a given volume of the colloidal sol. It serves as a quantitative measure of the stability of the colloidal sol, with higher Gold Numbers indicating greater protective power.

It comes out 2805

THE ANSWER GIVEN IN THE ANSWER KEY IS NOT 17 BUT .17 KINDLY RECHECK FIRST . Acc to Freundlich adsorption isotherm, x/m = k.c^1/n x/500 = 0.16 (0.65)^1/2.35 On solving, *x = 66.6g* Initially, we had 3L of 0.65 M ethanol solution i.e. 0.65 × 3 mol = 1.95 mol = 1.95 ×46 g = 89.7 g of ethanol Therefore, after adsorption, mass of ethanol in solution = 89.7 g - 66.6 g = 23.1 g = 23.1/46 mol = 0.502 mol of ethanol Molarity of left ethanol solution. = 0.502 mol/ 3L = 0.167 mol/L Hope it helps :)

B) when oxygen absorb electron then energy released in form of heat.
c) acc. to M.O.T , last electrons of O2 are in pi* so after absorbing electrons, e- increase in pi*.
d) when e- increase in pi* orbital, bond order of O2 decrease so bond length of O2 increase.

Reduction of AUCl3 with HCHO solution

AUCl3 can be reduced to Gold sol by using formaldehyde (HCHO) solution. This process involves the following steps:

Preparation of AUCl3 solution:
- Firstly, a solution of AUCl3 is prepared by dissolving gold trichloride in water.

Reduction with HCHO solution:
- Formaldehyde (HCHO) solution is then added to the AUCl3 solution under controlled conditions.
- The reduction of AUCl3 by formaldehyde leads to the formation of Gold sol.
- This reaction involves the transfer of electrons from formaldehyde to AUCl3, resulting in the reduction of gold ions to form Gold sol.

Characteristics of Gold sol:
- Gold sol is a colloidal solution of gold nanoparticles dispersed in a solvent.
- It exhibits unique optical properties due to the presence of nanoparticles, such as the red color observed in solutions of Gold sol.

Applications of Gold sol:
- Gold sol finds applications in various fields, including catalysis, electronics, and medicine.
- It is used in the preparation of nanomaterials and as a catalyst in organic synthesis reactions.

In conclusion, the reduction of AUCl3 with HCHO solution is an effective method for the preparation of Gold sol, which has diverse applications in different industries.

The stability of lyophobic sols is due to the charge on particles.

Explanation:
Lyophobic sols are colloidal sols in which the dispersed phase (colloidal particles) has little or no affinity for the dispersion medium. This means that the particles are not easily dispersed in the medium and tend to aggregate or settle quickly. However, the stability of lyophobic sols is achieved by introducing charges on the particles.

The charge on particles in lyophobic sols is usually achieved through the process of adsorption. When a lyophobic sol is prepared, the dispersion medium is treated with a suitable electrolyte. This electrolyte dissociates into positive and negative ions, and these ions get adsorbed on the surface of the particles. The adsorption of these ions imparts a charge to the particles, creating a stable colloidal system.

The charge on particles plays a crucial role in stabilizing lyophobic sols. Here's why:

1. Electrostatic Repulsion: The like-charged particles repel each other due to electrostatic forces. This repulsion prevents the particles from coming close together and aggregating. As a result, the sol remains stable and the particles stay dispersed.

2. Steric Stabilization: In addition to electrostatic repulsion, charged particles may also have adsorbed layers of molecules or ions that create a physical barrier around the particle. This is known as steric stabilization. The adsorbed layers prevent the particles from approaching each other closely, further enhancing the stability of the sol.

3. Prevention of Coagulation: The charge on particles hinders the process of coagulation or flocculation. Coagulation occurs when colloidal particles come together to form larger aggregates. The charged particles repel each other, making it difficult for coagulation to occur.

4. Redispersion: If the sol undergoes slight flocculation or settles, it can be easily redispersed by gentle shaking or stirring. The charged particles will disperse again due to repulsion forces.

In summary, the stability of lyophobic sols is primarily due to the charge on particles. This charge creates repulsion forces that prevent aggregation and coagulation of particles, thus maintaining the sol's stability.

The order of adsorption of gases NH3, CO2 and H2 by 1 g charcoal at 300 K and 1 atm pressure is given by option 'B', i.e., NH3, CO2, H2.

Explanation:
Adsorption is the process of accumulation of molecules of a substance on the surface of another substance. In this case, the gases NH3, CO2, and H2 are adsorbed by 1 g charcoal at 300 K and 1 atm pressure. The order of adsorption is determined by the force of attraction between the gas molecules and the charcoal surface.

NH3 has the highest order of adsorption because it has the highest dipole moment among the three gases. The dipole moment of NH3 allows it to form hydrogen bonds with the polar surface of charcoal, which results in a stronger force of attraction between NH3 and charcoal.

CO2 has the second-highest order of adsorption because it is a polar molecule and can form weak van der Waals forces with the surface of charcoal.

H2 has the lowest order of adsorption because it is non-polar and cannot form any significant interaction with the surface of charcoal.

Therefore, the order of adsorption of gases NH3, CO2, and H2 by 1 g charcoal at 300 K and 1 atm pressure is NH3 > CO2 > H2, which is given by option 'B'.

Admin is contradicting his/her own answer. In option a (II) is Chemisorption , now in option C (II) is Physisorption .How is this possible ?? a,d option should be correct.

Physical adsorption is the process by which a substance adheres to the surface of another substance through weak intermolecular forces. Chemical adsorption, on the other hand, involves the formation of chemical bonds between the adsorbate and the adsorbent. Let's analyze each statement to determine their accuracy.

a) Physical adsorption is multi-layer, non-directional, and non-specific

- Multi-layer: Physical adsorption can occur in multiple layers, meaning that the adsorbate molecules can stack on top of each other on the surface of the adsorbent. This is due to the weak van der Waals forces that are involved in physical adsorption.
- Non-directional: The forces involved in physical adsorption are non-directional, meaning that they act equally in all directions. This lack of directionality allows the adsorbate molecules to be easily removed from the surface of the adsorbent.
- Non-specific: Physical adsorption is a non-specific process, meaning that it does not depend on the specific chemical properties of the adsorbate or the adsorbent. Any molecule that can interact with the surface through weak intermolecular forces can undergo physical adsorption.

b) Chemical adsorption is due to valence of atoms

- Chemical adsorption involves the formation of chemical bonds between the adsorbate and the adsorbent. These bonds are typically formed through the sharing or transfer of valence electrons between the atoms of the adsorbate and the adsorbent. Therefore, it is correct to say that chemical adsorption is due to the valence of atoms.

c) Physical adsorption is due to valence of atoms

- This statement is incorrect. Physical adsorption is not due to the valence of atoms. Instead, it is primarily governed by weak intermolecular forces such as van der Waals forces, dipole-dipole interactions, and hydrogen bonding. These forces arise from temporary fluctuations in electron distribution within molecules and do not involve the sharing or transfer of valence electrons.

d) Chemical adsorption is stronger than physical adsorption

- This statement is correct. Chemical adsorption is generally stronger than physical adsorption due to the formation of chemical bonds. Chemical bonds are typically stronger than intermolecular forces, resulting in a stronger adsorbate-adsorbent interaction. Chemical adsorption is often more difficult to reverse or remove compared to physical adsorption.

In summary, the correct statements are a) Physical adsorption is multi-layer, non-directional, and non-specific, b) Chemical adsorption is due to the valence of atoms, and d) Chemical adsorption is stronger than physical adsorption.

**Collodion:**
Collodion is a liquid preparation that is mainly used in medicine and photography. It is a solution of nitrocellulose in a mixture of alcohol and ether. When applied to the skin, collodion forms a flexible film that can be used for wound dressings or as a protective covering.

**Composition:**
Collodion is composed of a 4% solution of a specific substance in an alcohol-ether mixture. The correct answer is option D, nitrocellulose. Nitrocellulose is a highly flammable compound that is produced by nitrating cellulose with a mixture of nitric acid and sulfuric acid. It is commonly used in the production of explosives, lacquers, and films.

**Explanation:**
Nitrocellulose is the correct answer because it is the main ingredient in collodion. When nitrocellulose is dissolved in an alcohol-ether mixture, it forms a solution that can be easily applied to the skin. The alcohol and ether in the mixture help to dissolve the nitrocellulose and create a liquid solution.

When the collodion is applied to the skin, the alcohol and ether quickly evaporate, leaving behind a thin film of nitrocellulose. This film provides a protective barrier and helps to seal wounds. It can also be used as a base for applying medications or other substances to the skin.

**Other Options:**
The other options, nitroglycerin, cellulose acetate, and glycol dinitrate, are not correct answers because they are not commonly used in the preparation of collodion.

- Nitroglycerin: Nitroglycerin is a highly explosive compound that is used in the production of dynamite and as a medication for heart conditions. It is not commonly used in the preparation of collodion.

- Cellulose acetate: Cellulose acetate is a derivative of cellulose that is used in the production of films, fibers, and coatings. While it is similar to nitrocellulose, it is not commonly used in the preparation of collodion.

- Glycol dinitrate: Glycol dinitrate is an explosive compound that is used as a stabilizer in the production of dynamite. It is not commonly used in the preparation of collodion.

Therefore, the correct answer is option D, nitrocellulose.

Effect of Temperature on Gas Adsorption:
Factors affecting gas adsorption on a solid surface include temperature. Let's discuss how temperature influences the amount of gas adsorbed.

Effect of Temperature on Gas Adsorption:
- Increases with decrease in the temperature:
When the temperature decreases, the kinetic energy of gas molecules decreases, leading to a greater tendency for them to be adsorbed on the solid surface. This is due to the fact that at lower temperatures, the gas molecules have less energy to overcome the attractive forces of the solid surface, resulting in more adsorption.
- Decreases with increase in the temperature:
Conversely, when the temperature increases, the kinetic energy of gas molecules increases. This causes the gas molecules to have more energy to escape the attractive forces of the solid surface, leading to a decrease in the amount of gas adsorbed.
Therefore, the correct answer to the question is that the amount of gas adsorbed on a solid surface increases with a decrease in temperature.

Hydrophilic nature of Stearate ion:

Stearate ion is a negatively charged ion and is derived from stearic acid. It has a long hydrocarbon chain with a carboxylate group (-COO-) at the end. The hydrocarbon chain is nonpolar and hydrophobic in nature, whereas the carboxylate group is polar and hydrophilic in nature.

The hydrophilic nature of the stearate ion is due to the carboxylate group, which is made up of a carbonyl group (-C=O) and a hydroxyl group (-OH), both of which are polar in nature. The carbonyl group is electron-withdrawing, which causes the oxygen atom to become slightly negative, and the carbon atom to become slightly positive. Similarly, the hydroxyl group is electron-donating, which causes the oxygen atom to become slightly negative, and the hydrogen atom to become slightly positive.

The polar nature of the carboxylate group makes it attracted to water molecules, and thus, hydrophilic in nature. This allows the stearate ion to dissolve in water and form a stable solution.

Conclusion:

In conclusion, the head of the stearate ion, which is the carboxylate group, is hydrophilic in nature due to its polar nature.