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According to the equation ∆G = ∆H – T∆S For a process to be spontaneous, ∆G should be negative. ∆H of adsorption is always negative. For a gas. ∆S is also negative. Thus, in an adsorption process, which is spontaneous, a. combination of these two factors always makes ∆G negative.

(c) Al₂(SO₄)₃

1. Effect of size of the particles of adsorbent:

Greater the specific area of the solid available for adsorption of adsorbent, greater would be its adsorbing power. That is why porous or finely divided forms of adsorbents more strongly. However, the size of pores should be large enough to allow the diffusion of gas molecules.

2. Effect of pressure:

Increase in pressure initially increases the adsorption which later attains equilibrium at high pressure.

\(\frac{x}{m}\) = kP^1/n (n>1)

1. Due to the formation of chemical bond between adsorbate and adsorbent.

2. 4% solution of nitro cellulose in a mixture of alcohol and ether. 

3. Peptisation is the process of converting a precipitate into colloidal sol by adding an electrolyte. Rut coagulation is the settling of colloidal particles

(a) peptisation

(c) (i) & (ii)

Emulsion can be separated into two separate layers. This process is called Deemulsification. Various deemulsilication techniques are given below. 

1. Distilling of one component 

2. Adding an electrolyte to destroy the charge. 

3. Destroying the emulsifier using chemical methods. 

4. Using solvent extraction to remove one component. 

5. By freezing one of the components. 

6. By applying centrifugal force. 

7. Adding dehydrating agents for water in oil type. 

8. Using ultrasonic waves. 

9. Heating at high pressures.

(b) optimum temperature

(a) (i) & (ii)

Enzymes can be active in human body at a temperature of 98°F

1. The path of light becomes visible when passed through a colloidal solution while it is not visible in case of a true solution. This is because of Tyndall effect caused by the scattering of light by colloidal particles. 

2. Applications of adsorption: 

• Activated charcoal is used in gas masks to remove poisonous gases such as CH₄ , CO, etc. 
• Animal charcoal is used as decoloriser in the manufacture of sugar. 
• Silica is used for removing moisture.
• The ion exchange resins are used for removing hardness of water.

(d) hydrolysis of sucrose in the presence of dilute hydrochloric acid

1. The surfiice of a catalyst is not smooth. It bears steps, cracks and corners. Hence the atoms on such locations of the surface are coordinatively unsaturated. 

2. The have residual force of attraction. Such sites are called active centres. So the surface cames high surface free energy.

(b) Langmuir

(a) Both A and R are correct and R is the correct explanation of A.

1. Active centres increases the rate of the reaction by adsorbing and activating the reactants. 

2. Increase in the activity of a catalyst by increasing the surface area. Increase in the surface area of metals and metal oxides by reducing the particle size increases the rate of the reaction. 

3. The action of catalytic poison occurs when the poison blocks the active centres of the catalyst. 

4. A promoter (or) activator increases the number of active centres on the surface.

(a) Both A and R are correct but R is the correct explanation of A.

Peptisation. It is a dispersion method of preparation ofcoiloid whereas others are condensation methods of preparation of colloids.

(c) a (or) b

Decomposition of H₂O₂ by Pt. It is heterogeneous catalysis whereas others are homogeneous catalysis.

The negative catalyst in the decomposition of H₂O₂ is Ethanol

A catalytic poison for Pt catalyst Co

The catalyst poison in contact process of manufacture of SO₃ is As₂O₃

(d) Chromatography

(c) electrophoresis

(a) Cataphoresis

(a) haemoglobin

(c) Basic dyes

(iii) By addition of lyophilic sol.

Clay is a negatively charged colloid.

Pt is a negatively charged colloid

(ii), (iv)

(ii) Presence of equal and similar charges on colloidal particles provides stability to the colloids.

(iv) Brownian movement stabilises sols.

(ii), (iv)

(ii) adding more amount of dispersion medium

(iv) adding emulsifying agent

In sol, the dispersed phase-Solid

Dispersion medium-Liquid 

Example: Paint 

In Emulsion, the dispersed phase is liquid and dispersion medium is also liquid. 

Example: Milk.

The expression for Fruendlich adsorption isotherm :

x/m= kp^1/n

Oil in water: Milk/vanishing cream.

Water in oil: Butter/cold cream.

(1) Binding of enzyme to substrate to form an activated complex.

E + S → ES*

(2) Decomposition of the activated complex to from the product.

ES* → E + P

(i) A gel is a colloidal solution in which dispersed phase is a liquid and dispersion medium is a solid. ex- jellies 

(ii) When the reactants, products and catalyst are in the same physical states the catalysis is called homogeneous catalysis. 

(iii) A sol is a colloidal solution in which dispersed phase is a solid and dispersion medium is a liquid. 

Sol: Paint/cell fluids.

Gel : Cheese/butter/jellies 

(i) The positively charged colloidal particles of Fe(OH)₃ get coagulated by the positively charged Cl- ions provided by NaCl. 

(ii) On passing direct current, colloidal particles move towards the positively charged electrode where they lose their charge and get coagulated. 

(iii) Scattering of light by the colloidal particles takes place and the path of light becomes visible (Tyndall effect).

Due to collision between particles. 

Molybdenum the promoter used in Haber’s process .

A plot between the amount of adsorbate adsorbed and pressure or concentration of adsorbate at constant temperature is called adsorption isotherm.

1. Mo (or) Al₂O₃

2. AS₂O₃ catalyst poison

3. CH₃COOH 

4. ethanol (or) Glycerol, negative catalyst

5. Activation energy

6. intermediate compound formation

7. CuCI₂

8. MnO₂ , intermediate compound formation theory 

9. heterogeneous catalysis

10. adsorption

CO acts as poison catalyst for Haber’s process and lowers the activity of solution therefore it is necessary to remove when NH₃ obtained by Haber’s process. 

(d) Tyndall effect-scattering of light

(ii) Adsorption of ionic species from solution. 

(a) (i) & (ii)

(b)  3 4 2 1

(i) ΔH > 0 is not applicable to the phenomenon of adsorption.