CBSE Class 12 Chemistry Surface Chemistry MCQs Set C

Question. Which of the following reactions is an example of heterogeneous catalysis?

Answer : D

Question. Formation of ammonia from H2 and N2 by Haber’s process using Fe is an example of
(a) heterogeneous catalysis
(b) homogeneous catalysis
(c) enzyme catalysis
(d) non-catalytic process

Answer : A

Question. Peptisation involves
(a) precipitation of colloidal particles
(b) disintegration of colloidal aggregates
(c) evaporation of dispersion medium
(d) Impact of molecules of the dispersion medium on the colloidal particles

Answer : B

Question. A colloidal system has particles of which of the following size?
(a) 10^–9 m to 10^–12 m
(b) 10^–6 m to 10^–9 m
(c) 10^–4 m to 10^–10 m
(d) 10^–5 m to 10^–7 m

Answer : B

Question. Measuring zeta potential is useful in determining which property of colloidal solution?
(a) Viscosity
(b) Solubility
(c) Stability of the colloidal particles
(d) Size of the colloidal particles

Answer : C

Question. The Langmuir adsorption isotherm is deduced using which of the following assumptions?
(a) The adsorption takes place in multilayer
(b) The adsorbed molecules interact with each other
(c) The adsorption sites are equivalent in their ability to absorb the particles
(d) The heat of adsorption varies with coverage

Answer : C

Question. In the Freundlich adsorption equation x/m = kp^1/n ,  the value of n is
(a) always greater than one
(b) always smaller than one
(c) always equal to one
(d) greater than one at low temperature and smaller than one at high temperature

Answer : A

Question. Adsorption is a surface phenomenon because
(a) adsorbent has large surface area
(b) chemical compounds formed are not on the surface of adsorbent
(c) only the surfaces of the adsorbent have unutilised valencies
(d) None of the options

Answer : C

Question. In Langmuir’s model of adsorption of a gas on a solid surface,
(a) the rate of dissociation of adsorbed molecules from the surface does not depend on the surface covered
(b) the adsorption at a single site on the surface may involve multiple molecules at the same time
(c) the mass of gas striking a given area of surface is proportional to the pressure of the gas
(d) the mass of gas striking a given area of surface is independent of the pressure of the gas

Answer : C

Question. In which of the following reactions, heterogeneous catalysis is involved?
(i) 2SO₂ (g) +O₂(g) →^NO(g) 2SO3NO(g)
(ii) 2SO₂(g) →^Pt(s) 2SO₃ 
(iii) N₂(g) + 3H₂(g) →^Fe(s) 2SO₃(g)
(iv) CH₃COOCH₃ (/) + H₂O→HCl ^(/)     
                                CH₃COOH(aq)+ CH₃OH(aq) 
(a) (ii) and (iii)
(b) (ii), (iii) and (iv)
(c) (i), (ii) and (iii)
(d) Only (iv)

Answer : A

Question. Which is not correct regarding the adsorption of a gas on surface of a solid?
(a) On increasing temperature adsorption increases continuously.
(b) Enthalpy and entropy change is negative.
(c) Adsorption is more for some specific substance.
(d) It is a reversible reaction.

Answer : A

Question. Which one of the following statements is not correct?
(a) The value of equilibrium constant is changed in the presence of a catalyst in the reaction at equilibrium.
(b) Enzymes catalyse mainly biochemical reactions.
(c) Coenzymes increase the catalytic activity of enzyme.
(d) Catalyst does not initiate any reaction.

Answer : A

Question. Which one of the following statements is incorrect about enzyme catalysis?
(a) Enzymes are mostly proteinous in nature.
(b) Enzyme action is specific.
(c) Enzymes are denatured by ultraviolet rays and at high temperature.
(d) Enzymes are least reactive at optimum temperature.

Answer : D

Question. The enzyme which hydrolyses triglycerides to fatty acids and glycerol is called
(a) maltase
(b) lipase
(c) zymase
(d) pepsin.

Answer : B

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

Answer : D

Question. For a linear plot of log(x /m ) versus log p in a Freundlich adsorption isotherm, which of the following statements is correct? (k and n are constants)
(a) 1/n appears as the intercept
(b) Only 1/n appears as the slope
(c) log (1/n) appears as the intercept
(d) Both k and 1/n appear in the slope term

Answer : B

Question. Given below, catalyst and corresponding process/ reaction are matched. The mismatch is
(a) [RhCl(PPh₃)₂] : Hydrogenation
(b) TiCl₄ + Al(C₂H₅)₃ : Polymerisation
(c) V₂O₅ : Haber : Bosch process
(d) Nickel : Hydrogenation  

Answer : C

Question. The decomposition of H₂O₂ may be checked by adding small quantity of phosphoric acid. This is an example of
(a) neutralisation
(b) negative catalysis
(c) positive catalysis
(d) catalytic poisoning

Answer : B

Question. Surface area per gram of the adsorbent is called
(a) molar surface area
(b) normal surface area
(c) specific surface area
(d) equivalent surface area

Answer : C

Question. Which one of the following characteristics is not correct for physical adsorption?
(a) Adsorption on solids is reversible
(b) Adsorption increases with increase in temperature
(c) Adsorption is spontaneous
(d) Both enthalpy and entropy of adsorption are negative

Answer : B

Question. Which of the following reaction requires catalyst?
(a) S + O₂ → SO₂
(b) C + O₂ → CO₂
(c) 2SO₂ + O₂ → 2SO₃
(d) All of the options  

Answer : C

Question. In a chemical reaction, catalyst
(a) decreases the energy of activation
(b) increases the energy of activation
(c) does not change energy of activation
(d) None of the options

Answer : A

Question. Assertion (A) Catalyst increases the rate of a reaction.
Reason (R) In presence of a catalyst, the activation energy of the reaction increases. The correct answer is
(a) Both A and R are correct and R is the correct explanation of A
(b) Both A and R are correct but R is not the correct explanation of A
(c) A is correct but R is incorrect
(d) Assertion is not correct, but Reason is correct

Answer : C

Question. A catalyst
(a) lowers the activation energy
(b) changes the rate constant
(c) changes the product
(d) itself destroys in the reaction

Answer : A

Question. Catalyst in a reaction
(a) lowers the activation energy
(b) increases the rate of reaction
(c) Both (a) and (b)
(d) initiates the reaction

Answer : C

Question. Which one of the following reactions is an example of auto-catalysis?
(a) 2AsH₃(s) → 2As(s) + 3H₂(g)
(b) N₂(g) + 3H₂(g) →^Fe(g) 2NH₃(g)
(c) 2SO₂(g) + O₂(g) →^No(g) 2SO₃(g)
(d) C₁₂H₂₂O₁₁(/) + H₂O(/) →^H+(/) C₆H₁₂O₆ (/) + C₆H₁₂O₆(/)  

Answer : A

Question. Amount of gas adsorbed per gram of adsorbent increases with pressure, but after certain limit is reached, adsorption becomes constant. It is due to
(a) multilayers are formed
(b) desorption takes place
(c) temperature is increased
(d) absorption also starts

Answer : A

Question. Which of the following assumptions is not correct about Langmuir adsorption isotherm?
(a) The solid surface is homogeneous and has a fixed number of adsorption sites
(b) Every adsorption site is equivalent
(c) The adsorbed layer is not uniform all over the adsorbent
(d) The adsorbed gas behaves ideally in the vapour phase

Answer : C

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

Answer : C

Question. Random motion of colloidal particles is known as
(a) Dialysis
(b) Brownian movement
(c) Electroosmosis
(d) Tyndall effect

Answer : B

Question. Identify the correct statement regarding enzymes.
(a) Enzymes are specific biological catalysts that can normally function at very high temperatures (T – 1000 K)
(b) Enzymes are normally heterogeneous catalysts that are very specific in their action
(c) Enzymes are specific biological catalysts that cannot be poisoned
(d) Enzymes are specific biological catalysts that possess well defined active sites

Answer : D

Question. Active charcoal is a good catalyst because
(a) made up of carbon atoms
(b) is very reactive
(c) has more adsorption power
(d) has inert nature toward reagent

Answer : C

Question. Which mixture of the solutions will lead to the formation of negatively charged colloidal [AgI]I– sol ?
(a) 50 mL of 0.1 M AgNO₃ + 50 mL of 0.1 M KI
(b) 50 mL of 1 M AgNO₃ + 50 mL of 1.5 M KI
(c) 50 mL of 1 M AgNO₃ + 50 mL of 2 M KI
(d) 50 mL of 2 M AgNO₃ + 50 mL of 1.5 M KI

Answer : B

Question. On which of the following properties does the coagulating power of an ion depend?
(a) The magnitude of the charge on the ion alone
(b) Size of the ion alone
(c) Both magnitude and sign of the charge on the ion
(d) The sign of charge on the ion alone

Answer : C