Chapter 11

The adsorption of a gas, on a solid surface, varies with pressure of the gas in which of the following manner? (a) slow \longrightarrow fast \(\longrightarrow\) independent of the pressure (b) fast \(\longrightarrow\) slow \(\longrightarrow\) independent of the pressure (c) independent of the pressure \(\longrightarrow\) slow \(\longrightarrow\) fast (d) independent of the pressure \(\longrightarrow\) fast \(\longrightarrow\) slow

Lyophilic sols are more stable than lyophobic sols because the particles (1) are positively charged (2) are negatively charged (3) are solvated (4) repel each other (5) are heavy (a) 2,3 and 4 (b) 2 and 3 (c) 1,2 and 5 (d) 3 only

Potassium stearate is obtained by the saponification of an oil or fat. It has the formula \(\mathrm{CH}_{3}-\left(\mathrm{CH}_{2}\right)_{16}-\mathrm{COO}^{-} \mathrm{K}^{+} .\)The molecule has a lyopho- bic end \(\left(\mathrm{CH}_{3}\right)\) and a lyophilic and \(\mathrm{COO}^{-} \mathrm{K}^{+}\). Potassium stearate is an example of (1) lyophobic colloid (2) associated colloid or micelle (3) multimolecular colloid (4) macromolecular colloid (a) 2 only (b) 1 and 2 (c) 3 and 4 (d) 4 only

Which of the following factors are responsible for the increase in the rate of a surface catalysed reaction? 1\. A catalyst provides proper orientation for the reactant molecules to react. 2\. Heat of adsorption of reactants on a catalyst helps reactant molecules to overcome activation energy. 3\. The catalyst increases the activation energy of the reaction. 4\. Adsorption increases the local concentration of reactant molecules on the surface of the catalyst. Select the correct answer using the code given below: (a) 1 and 2 (b) 1 and 3 (c) 2,3 and 4 (d) 1,2 and 4 .

Choose the incorrect statement for chemical adsorption (1) value of adsorption enthalpy is above \(-20.0 \mathrm{kJmol}^{-1}\) (2) van der Waals forces exist between the adsorbent and the adsorbate (3) usually monomolecular layer is formed on the adsorbent (4) multimolecular layer may be formed on the adsorbent (a) 1,2 and 3 (b) 2,3 and 4 (c) 1,2 and 4 (d) \(1,2,3\) and 4

Which of the following process does not occur at the interface of phases (a) Hetergenous catalysis (b) Homogeneous catalysis (c) Corrosion (d) Crystallisation

Which of the following interface cannot be obtained? (a) Solid-liquid (b) Liquid-liquid (c) Liquid-gas (d) Gas-gas

Extent of physisorption of a gas increases with (a) Increase in temperature (b) Decrease in temperature (c) Decrease in strength of van der Walls forces (d) Decrease in surface area of adsorbent.

Which one of the following is not applicable to the phenomenon of adsorption? (a) \(\Delta \mathrm{G}<0\) (b) \(\Delta \mathrm{S}<0\) (c) \(\Delta H<0\) (d) \(\Delta \mathrm{H}>0\)

Which of the following is not a favourable condition for physical adsorption? (a) Negative \(\Delta \mathrm{H}\) (b) High pressure (c) High temperature (d) Higher critical temperature of adsorbate

Physical adsorption of a gaseous species may change to chemical adsorption with (a) Increase in temperature (b) Decrease in temperature (c) Decrease in surface area of adsorbent (d) Increase in surface area of adsorbent

In physisorption adsorbent does not show specificity for any particular gas because (a) Enthalpy of adsorption is low (b) It is a reversible process (c) Gases involved behave like ideal gases (d) Involved van der Waals forces are universal.

Which of the following is an example of absorption? (a) Oxygen on metal surface (b) Hydrogen on finely divided nickel (c) Water on calcium chloride (d) Water on silica gel

On the basis of data given below predict which of the following gases shows least adsorption on a definite amount of charcoal? Gas \(\mathrm{CO}_{2} \quad \mathrm{SO}_{2} \quad \mathrm{CH}_{4} \quad \mathrm{H}_{2}\) Critical temp./K \(\quad 304 \quad 630\) \(190 \quad 33\) (a) \(\mathrm{SO}_{2}\) (b) \(\mathrm{CH}_{4}\) (c) \(\mathrm{H}_{2}\) (d) \(\mathrm{CO}_{2}\)

In which of the following reactions heterogenous catalysis is involved? (i) \(2 \mathrm{SO}_{2}(\mathrm{~g})+\mathrm{O}_{2}(\mathrm{~g}) \stackrel{\mathrm{No}(\mathrm{g})}{\longrightarrow} 2 \mathrm{SO}_{3}(\mathrm{~g})\) (ii) \(2 \mathrm{SO}_{2}(\mathrm{~g}) \stackrel{\mathrm{P}(\mathrm{S})}{\longrightarrow} 2 \mathrm{SO}_{3}(\mathrm{~g})\) (iii) \(\mathrm{N}_{2}(\mathrm{~g})+3 \mathrm{H}_{2}(\mathrm{~g}) \stackrel{\mathrm{Fe}(\mathrm{S})}{\longrightarrow} 2 \mathrm{NH}_{3}(\mathrm{~g})\) (iv) \(\mathrm{CH}_{3} \mathrm{COOCH}_{3}(\mathrm{I})+\mathrm{H}_{2} \mathrm{O}(\mathrm{I}) \stackrel{\mathrm{HCl}(\mathrm{l})}{\longrightarrow} \mathrm{CH}_{3} \mathrm{COOH}\) \(+(a q)+C H_{3} O H(a q)\) (a) (ii), (iii) (b) (ii), (iii), (iv) (c) (i), (ii), (iii) (d) (iv)

At high concentration of soap in water, soap behaves as (a) Molecular colloid (b) Lyophilic colloid (c) Macromolecular colloid (d) Associated colloid

Which of the following will show Tyndall effect? (a) Aqueous solution of soap above critical micelle concentration (b) Aqueous solution of soap below critical micelle concentration (c) Aqueous solution of sugar (d) Aqueous solution of sodium chloride

Method by which lyophobic sol can be protected. (a) By addition of an electrolyte (b) By addition of oppositely charged sol. (c) By addition of lyophilic sol. (d) By bhoiling

Freshly prepared precipitate sometimes gets converted to colloidal solution by (a) Electrolysis (b) Coagulation (c) Peptisation (d) Diffusion

Which of the following electrolytes will have maximum coagulating value for \(\mathrm{Agl} / \mathrm{Ag}^{+}\)sol? (a) \(\mathrm{Na}_{3} \mathrm{PO}_{4}\) (b) \(\mathrm{Na}_{2} \mathrm{SO}_{4}\) (c) \(\mathrm{NaCl}\) (d) \(\mathrm{Na}_{2} \mathrm{~S}\)

A colloidal system having a solid substance as a dispersed phase and a liquid as a dispersion medium is classified as (a) Solid sol (b) Emulsion (c) Sol (d) Gel

The values of colligative properties of colloidal solution are of small order in comparison to those shown by true solutions of same concentration because of colloidal particles (a) Remain suspended in the dispersion medium (b) Form lyophilic colloids (c) Are comparatively less in number (d) Exhibit enormous surface area

Which of the following process is responsible for the formation of delta at a place where rivers meet the sea? (a) Coagulation (b) Peptisation (c) Emulsification (d) Colloid formation

Which of the following process is not responsible for the presence of electric charge on the sol particles? (a) Adsorption of ionic species from solution (b) Electron capture by sol particles (c) Absorption of ionic species from solution (d) Formation of Helmholtz electrical doable layer.

Which is correctly matched? (a) Erionite \(\mathrm{Na}_{2} \mathrm{~K}_{2} \mathrm{CaMg}\left(\mathrm{AlO}_{2}\right)_{2}\left(\mathrm{SiO}_{2}\right)_{2} \cdot 6 \mathrm{H}_{2} \mathrm{O}\) (b) Anionic surfactant \(-\mathrm{C}_{17} \mathrm{H}_{35} \mathrm{COONa}\) (c) Cationic surfactant - (d) None of these

A catalyst (a) Increases the frequency of collision of reacting species. (b) Alters the reaction mechanism. (c) Decreases the activation energy (d) Increases the average kinetic energy of the reacting molecules.

Identify the wrong statements. (a) On dissolving a detergent in water, its surface tension is increased. (b) Phenol and benzoic acid can be distinguished using \(\mathrm{NaOH}\) aqueous solution. (c) Langmuir adsorption theory explains chemical adsorption. (d) Valence bond theory of complexes explain the colour of complexes.

Which among the following are lyophilic in nature? (a) Gold (b) Gum (c) Starch (d) Gelatin

Emulsion can be destroyed by (a) The addition of an emulsifier which tends to form an emulsion of the same type. (b) Freezing (c) Electrophoresis with a high potential (d) All of these

Which forms multi-layers during adsorption? (a) Van der Waal's adsorption (b) Chemical adsorption (c) Physical adsorption (d) All of these

Which colloids can be coagulated by \(\mathrm{Al}^{+3}\) here? (a) \(\mathrm{Al}_{2} \mathrm{~S}_{3}\) (b) \(\mathrm{CdS}\) (c) \(\mathrm{T}_{1} \mathrm{O}_{2}\) (d) Hae moglobin

Which of the following options are correct? (a) Micelle formation by soap in aqueous solution occurs above a particular concentration (b) Micelle formation by soap in aqueous solution is possible at all temperatures. (c) Soap solution behaves as a normal strong electrolyte at all concentrations. (d) On dilution of soap solution micelles may revert to individuals ions.

Which of the following statements are correct about solid catalyst? (a) Catalyst is required in large quantities to catalyse reactions. (b) Catalytic activity of a solid catalyst does not depend upon the strength of chemisorptions (c) Same reactants may give different product by using different catalysts. (d) Catalyst does not change \(\Delta \mathrm{H}\) of reaction.

\(\mathrm{H}_{2}\) gas is adsorbed on activated charcoal to a very little extend in comparison to easily liquefiable gases due to (a) Very strong van der Waal's interaction (b) Very high critical temperature (c) Very low critical temperature (d) Very weak van der Waals forces

Which of the following statements are correct? (a) Presence of equal and similar charges on colloidal particles provides stability to the colloids (b) Mixing two oppositely chartged sols neutralises their charges and stabilises the colloid. (c) Brownian movement stabilises sols (d) Any amount of dispersed liquid can be added to emulsion without destabilising it.

An emulsion cannot be broken by and (a) Adding more amount of dispersion medium (b) Heating (c) Adding emulsifying agent (d) Freezing

Which of the following substances will precipitate the negatively changed emulsions? (a) Glucose (b) Urea (c) \(\mathrm{NaCl}\) (d) \(\mathrm{KCl}\)

Which of the following colloids cannot be coagulaten easily? (a) Reversible colloids (b) Lyophillic colloids (c) Irreversible colloids (d) Lyophobic colloids

What happens when a lyophilic sol is added to a lyophobic sol? (a) Lyophilic sol is protected (b) Film of lyophobic sol is formed over lyophilic sol (c) Lyophobic sol is protected (d) Film of lyophltic sol is formed over lyophobic sol.

Which phenomenon occurs when electric field is applied to a colloid solution and electrophoresis is prevented. (a) Electroosmosis takes place (b) Reverse osmosis takes place (c) Dispersion medium becomes stationary (d) Dispersion medium begins to move

In a reaction, catalyst changes (a) Qualitatively (b) Physically (c) Quantitatively (d) Chemically

Which of the following phenomenon occurs when a chalk stick is dipped in ink? (a) Adsorption of solvent (b) Absorption and adsorption both of solvent (c) Absorption of solvent (d) Adsorption of coloured substance

Match the follow.ing Column-I (a) Dispersion medium moves in an electric field (b) Solvent molecules pass through semipermeable membrane towards soolvent side (c) Movement of charged colloidal particles under the influence of applied electric potential towards oppositely charged electrodes. (d) Solvent molecules pass through semi permeable membranes Column-II (p) Osmosis (q) Electrophoresis (r) Electroosmosis (s) Reverse Osmosis

Match the following \hline Column-I (a) Dialysis - (b) Peptisation (c) Emulsification Electrophoresis (d) Column-II (p) Cleansing action of soap (q) Coagulation (r) Colloidal sol formation (s) Purification

Match the following | Column-I | | :--- | | (a) Butter | | (b) Pumice | | stone | | (c) Milk | | (d) Paints | Column-II (p) Dispersion of liquid in liquid (q) Dispersion of solid in liquid (r) Dispersion of gas in solid (s) Dispersion of liquid in solid

Assertion: When freshly precipitated nickel sulphide (NiS) is shaken with a solution of hydrogen sulphide, a colloidal solution is obtained. Reason: A colloidal solution is stable because all the colloidal particles carry same charge

Assertion: Finely divided solid reactants react much faster as compared to massive reactants. Reason: Finely divided solid reactants possess a large surface area.

Assertion: When \(\mathrm{AgNO}_{3}\) is treated with excess of potassium iodide, colloidal particles gets attracted towards anode. Reason: Colloidal particles adsorb common ions and thus become charged.

Assertion: Lower is the gold number of a protective colloid, higher is its protective power. Reason: Gold number gives an identification of the charge on a colloidal solution of Protective Colloid.

Assertion: Colloidal solutions do not show Brownian motion. Reason: Brownian motion is responsible for stability of sols.