Chapter 11

Colloidal solution of silver is prepared by (a) Bredig's arc method (b) peptization (c) colloidal milk (d) double decomposition method

When a few typical solutes are separated by a particular selective membrane, such as protein particles from blood corpuscles, the process is called (a) exosmosis (b) dialysis (c) transpiration (d) endosmosis

Alum purifies muddy water by (a) absorption (b) dialysis (c) emulsifying properties (d) coagulation

In which of the following Tyndall effect is not observed? (a) gold sol (b) sugar solution (c) emulsions (d) suspension

The movement of colloidal particle under the influence of electric field is called (a) electro dialysis (b) electro osmosis (c) electrolysis (d) electrophoresis

Which of the following has maximum flocculation value for a negatively charge sol? (a) \(\mathrm{BaCl}_{2}\) (b) \(\mathrm{NaCl}\) (c) \(\mathrm{AlCl}_{3}\) (d) \(\mathrm{MgCl}_{2}\)

The capacity of an ion to coagulate a colloidal solution depends upon (a) nature of charge (b) amount of charge (c) its shape (d) both (a) and (b)

Which of the following is used for the destruction of colloids? (a) ultrafiltration (b) adding electrolyte (c) both (a) and (b) (d) dialysis

The movement of colloidal particles towards the oppositely charged electrodes on passing electric current is known as (a) Tyndall effect (b) cataphoresis (c) Brownian movement (d) none of these

Which of the following colloidal solution is used in photography? (a) colloidal silver bromide (b) colloidal gold (c) colloidal silver (d) colloidal sulphur

Cod liver is an example of (a) oil emulsion (b) oil in water emulsion (c) water in oil emulsion (d) water in water emulsion

The efficiency of an enzyme to catalyse a reaction is due to its capacity to (a) reduce the activation energy of the reaction (b) form strong enzyme substrate complex (c) decrease the bond energy of all substrate molecules (d) increase the free energy of the catalyst substrate reaction (e) alter the substrate geometry to fit into the shape of the enzyme molecule.

An emulsifier is a substance which (a) stabilizes the emulsion (b) coagulates the emulsion (c) retards the dispersion of liquid in liquid (d) causes homogenesis of emulsion

The process of separating cream from milk is called (a) emulsification (b) demulsification (c) emulsions (d) electro-osmosis

Which of the following process is responsible for the digestion of fats in the intestines? (a) electro-osmosis (b) demulsification (c) electrophoresis (d) emulsification

The ability of a catalyst to accelerate the chemical reaction is known as (a) selectivity (b) activity (c) positive catalysis (d) negative catalysis

A catalyst in a chemical reaction (a) decreases rate constant of the reaction (b) reduces enthalpy of the reaction (c) does not affect equilibrium constant of the reaction (d) increases activation energy of the reaction

Homogeneous catalysis implies that (a) reactants and products must be in the same phase (b) reactants and catalyst must be in the same phase (c) composition of the reaction mixture must be homogeneous throughout (d) products and the catalyst must be in the same phase

In homogeneous catalytic reactions, the rate of reaction (a) depends upon the concentration of catalyst (b) depends upon physical state of catalyst (c) is independent of the physical state of catalyst (d) is independent of the concentration of catalyst

In the reaction \(\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}(\mathrm{~s})+\mathrm{H}_{2} \mathrm{O}(\mathrm{1}) \stackrel{\mathrm{Dal} \mathrm{H}_{2} \mathrm{SO}}{\leftrightarrow} \mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}(\mathrm{aq})\) \(+\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}(\mathrm{aq})\) dilute \(\mathrm{H}_{2} \mathrm{SO}_{4}\) acts as (a) homogeneous catalyst (b) heterogenous catalyst (c) heterogeneous reactant (d) homogeneous reactant

Which of the following kinds of catalysis can be explained by the adsorption theory? (a) Enzyme catalysis (b) Homogeneous catalysis (c) Acid base catalysis (d) Heterogeneous catalysis

Which of the following is an example of heterogeneous catalyst? (a) \(2 \mathrm{SO}_{2}+\mathrm{O}_{2}+2 \mathrm{H}_{2} \mathrm{O} \longrightarrow 2 \mathrm{H}_{2} \mathrm{SO}_{4}\) (b) \(2 \mathrm{H}_{2} \mathrm{O}_{2}(\mathrm{l})+\mathrm{MnO}_{2}(\mathrm{~s}) \longrightarrow 2 \mathrm{H}_{2} \mathrm{O}+\mathrm{O}_{2}\) (c) \(2 \mathrm{H}_{2} \mathrm{O}_{2}(\mathrm{aq}) \stackrel{\mathrm{FeCl}_{3}}{\longrightarrow} 2 \mathrm{H}_{2} \mathrm{O}+\mathrm{O}_{2}\) (d) sucrose \(+\mathrm{H}_{2} \mathrm{O} \longrightarrow{\mathrm{H}^{+}}{\longrightarrow}\) glucose \(+\) fructose

In case of auto catalysis (a) reactant catalyses (b) product catalyses (c) solvent catalyses (d) heat produced in the reaction catalyses

A biological catalyst is essentially (a) a carbohydrate (b) an enzyme (c) a nitrogen molecules (d) an amino acid

During micelle formation in the solution of surfactants (a) enthalpy change is positive but entropy change is negative (b) both the enthalpy and entropy are negative (c) enthalpy change is negative but entropy change is positive (d) both the enthalpy and entropy changes are positive

Which of the following is used as a catalyst for preparing Grignard reagent? (a) manganese dioxide (b) iron powder (c) activated charcoal (d) dry ether

Which of the following colloidal solution is prepared when very dilute solution of ferric chloride reacts with potassium ferrocyanide? (a) Prussian blue (b) Arsenic sulphide (c) Ferric hydroxide (d) Extrinsic colloid

Adsorption is a phenomenon, in which a substance (a) goes into the body of some other substance (b) accumulates on the surface of some other substance (c) remains close to some other substance (d) does not accumulate on the surface of some other substance

Which of the following statement is wrong about chemisorption? (1) it is reversible in nature (2) it is specific in nature (3) it first increases with increase in temperature and then pressure (4) it involves the formation of a compound on the surface of the solid adsorbent (a) 1 only (b) 2 and 3 (c) 1 and 3 (d) 2 and 4

The adsorption of solids, from a solution is called (a) chemical adsorption (b) physical adsorption (c) positive adsorption (d) negative adsorption

Eosine used to detect the end point of precipitation titration by adsorption is called (a) absorption indicator (b) adsorption indicator (c) normal indicator (d) chemical indicator

The amount of gas adsorbed physically on charcoal (a) increases with pressure and decreases with temperature (b) increases with temperature and decreases with pressure (c) increases with temperature and pressure (d) increases either temperature or pressure.

Freundlich adsorption isotherm gives a straight line on plotting (a) \(\mathrm{x} / \mathrm{m}\) vs \(\mathrm{P}\) (b) \(\log \mathrm{x} / \mathrm{m}\) vs \(\mathrm{P}\) (c) \(\log \mathrm{x} / \mathrm{m}\) vs \(\log \mathrm{P}\) (d) \(\mathrm{x} / \mathrm{m}\) vs \(1 / \mathrm{P}\)

A graph of adsorption isobar of chemisorption shows that adsorption 1(a) first decreases with temperature and then increases (b) first increases with temperature and then decreases (c) increases with temperature (d) decreases with temperature

If gold number of \(\mathrm{A}, \mathrm{B}, \mathrm{C}\) and \(\mathrm{D}\) are \(0.005,0.05,0.5\) and 5 respectively, then which of the following will have the greatest protective value? (a) \(\mathrm{A}\) (b) \(\mathrm{B}\) (c) \(\mathrm{C}\) (d) \(\mathrm{D}\)

The concentration of electrolyte required to coagulate a given amount of \(\mathrm{As}_{2} \mathrm{~S}_{3}\) solution is minimum in case of (a) potassium sulphate (b) aluminium nitrate (c) magnesium nitrate (d) potassium nitrate

Which of the following colloidal solution is commonly used as a germ killer? (a) colloidal sulphur (b) colloidal gold (c) colloidal silver (d) colloidal antimony

Colloidal solution commonly used in the treatment of eye disease is (a) colloidal silver (b) colloidal gold (c) colloidal antimony (d) colloidal sulphur

The bleeding from a wound is stopped by the application of ferric chloride as (a) blood starts flowing in the opposite direction (b) ferric chloride seals the blood vessels (c) blood reacts and a solid is formed which seals the blood vessels (d) blood is coagulated and the blood vessels are sealed.

According to the adsorption theory of catalysis, the speed of the reaction increases because (a) adsorption produces heat which increases the speed of the reaction (b) adsorption lowers the activation energy of the reaction (c) the concentration of reactant molecules at the active centres of the catalyst becomes high due to adsorption (d) in the process of adsorption, the activation energy of the molecules becomes large

Which one of the following reactions is an example of heterogeneous catalysis? (a) \(2 \mathrm{CO}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{~g}) \stackrel{\mathrm{NO}(\mathrm{g})}{\longrightarrow} 2 \mathrm{CO}_{2}\) (b) \(2 \mathrm{SO}_{2}(\mathrm{~g})+\mathrm{O}_{2}(\mathrm{~g}) \stackrel{\mathrm{NO}(\mathrm{g})}{\longrightarrow} 2 \mathrm{SO}_{3}\) (c) \(2 \mathrm{CO}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{~g}) \stackrel{\mathrm{PL}(\mathrm{S})}{\longrightarrow} 2 \mathrm{CO}_{2}\) (d) \(\mathrm{CH}_{3} \mathrm{CHO}(\mathrm{g}) \stackrel{\mathrm{I}_{2}(\mathrm{~g})}{\longrightarrow} \mathrm{CH}_{4}+\mathrm{CO}\)

Which of the following is incorrect? (1) Catalyst undergoes permanent chemical change. (2) Particle size of solute in true solutions is \(10^{-3} \mathrm{~m}\). (3) Starch solution is a hydrosol. (4) Hydrolysis of liquid ester in the presence of mineral acid is an example of heterogeneous catalysis reactions. (a) 1,2 and 3 (b) 2 and 3 (c) 1,2 and 4 (d) 2,3 and 4

Which of the following is an example of homogeneous catalysis reaction? (1) \(2 \mathrm{SO}_{2}(\mathrm{~g})+\mathrm{O}_{2}(\mathrm{~g}) \stackrel{\mathrm{NO}(\mathrm{g})}{\longrightarrow} 2 \mathrm{SO}_{3}(\mathrm{~g})\) (2) Hydrolysis of aqueous sucrose solution in the presence of aqueous mineral acid (3) \(2 \mathrm{H}_{2} \mathrm{O}_{2}(\mathrm{l}) \stackrel{\mathrm{Pl}(\mathrm{s})}{\longrightarrow} 2 \mathrm{H}_{2}(\mathrm{I})+\mathrm{O}_{2}(\mathrm{~g})\) (4) hydrolysis of liquid ester in the presence of aqueous mineral acid (a) 2 and 4 (b) 2 and 3 (c) 1,2 and 3 (d) 1,2 and 4

If \((\mathrm{x} / \mathrm{m})\) is the mass of adsorbate adsorbed per unit mass of adsorbent, \(p\) is the pressure of the adsorbate gas and a and \(\mathrm{b}\) are constants, which of the following represents Langmuir adsorption isotherm? (a) \(\log (\mathrm{x} / \mathrm{m})=\log (\mathrm{a} / \mathrm{b})+(1 / \mathrm{a}) \log \mathrm{p}\) (b) \(\mathrm{x} / \mathrm{m}=\mathrm{b} / \mathrm{a}+1 / \mathrm{ap}\) (c) \(\mathrm{x} / \mathrm{m}=1+\mathrm{bp} / \mathrm{ap}\) (d) \(1 /(x / m)=b / a+1 / a p\)

Adsorption of gases on solid surface is generally exothermic because (a) enthalpy is positive (b) entropy decreases (c) entropy increases (d) free energy increases

Which of the following is true in respect of adsorption? (a) \(\Delta \mathrm{G}<0 ; \Delta \mathrm{S}>0 ; \Delta \mathrm{H}<0\) (b) \(\Delta \mathrm{G}<0 ; \Delta \mathrm{S}<0 ; \Delta \mathrm{H}<0\) (c) \(\Delta \mathrm{G}>0 ; \Delta \mathrm{S}>0 ; \Delta \mathrm{H}<0\) (d) \(\Delta \mathrm{G}<0 ; \Delta \mathrm{S}<0 ; \Delta \mathrm{H}>0\)

The catalyst used in Zeigler process for polyethylene manufacture (a) consists of aluminium triethyl and titanium tetrachloride (b) is vanadium pentoxide (c) consists of aluminium chloride and titanium dioxide (d) is finely divided nickel

Langmuir's adsorption equation which describes the amount of gas adsorbed on a solid surface is written as \(\frac{\mathrm{p}}{\mathrm{x} / \mathrm{m}}=\frac{1}{\mathrm{ab}}+\frac{\mathrm{p}}{\mathrm{b}}\) Here \(\mathrm{x} / \mathrm{m}\) is the extent of adsorption, a and \(\mathrm{b}\) are constants, and \(\mathrm{p}\) is the gas pressure. On the basis of the above equation indicate which of the following statements is correct? (1) At low value of \(\mathrm{p}, \mathrm{x} / \mathrm{m} \propto \mathrm{p}\). (2) At high value of \(\mathrm{p}, \mathrm{x} \longrightarrow \mathrm{b}\) (adsorption is independent of pressure). (3) Between the low and high value of \(\mathrm{p}\), the above equation becomes \(x / m=k p^{1 / n}\) which is the Freundlich equation (here \(\mathrm{k}\) and \(\mathrm{n}\) are constants) (a) 1 and 2 (b) 2 and 3 (c) \(\mathbb{l}\) and 3 (d) 1,2 and 3

Which of the following statements are correct? (1) The smaller the gold number of a lyophilic colloid, the larger will be its protective power. (2) Lyophilic sols in contrast to lyophobic sols, are easily coagulated on addition of small amounts of electrolytes. (3) Ferric chloride solution is used to stop bleeding from a fresh cut because it coagulates blood. (4) The flocculation value of arsenious sulphide sol is independent of the anion of the coagulating electrolyte. Select the correct answer using the codes given below: (a) 1,2 and 4 (b) 1,2 and 3 (c) 1,3 and 4 (d) 2,3 and 4

On breaking a cubic solid (edge \(=1 \mathrm{~m}\) ) into fine cubic particles of edge \(1 \mu \mathrm{m}\) surface becomes (a) remains same (b) 100 times (c) 1000 times (d) 1000,000 times