Please refer to Chapter 5 Surface Chemistry MCQ Class 12 Chemistry with answers below. These multiple-choice questions have been prepared based on the latest NCERT book for Class 12 Chemistry. Students should refer to MCQ Questions for Class 12 Chemistry with Answers to score more marks in Grade 12 Chemistry exams. Students should read the chapter Surface Chemistry and then attempt the following objective questions.

MCQ Questions Class 12 Chemistry Chapter 5 Surface Chemistry

The Surface Chemistry MCQ Class 12 Chemistry provided below covers all important topics given in this chapter. These MCQs will help you to properly prepare for exams.

Question. How many layers are adsorbed in chemical adsorption?
(a) One
(b) Two
(c) Many
(d) Zero

Question. Which of the following statements is not correct ?
(a) Physical adsorption is due to van der Waal’s forces
(b) Chemical adsorption first decreases with increase in temperature.
(c) Physical adsorption is reversible
(d) Adsorption energy for a chemical adsorption is generally greater than that of physical adsorption.

Question. Adsorption of gases on solid surface is exothermic reaction because
(a) free energy increases
(b) enthalpy is positive
(c) entropy increases
(d) enthalpy is negative

Question. Adsorbed acetic acid on activated charcoal is:
(a) adsorber
(b) absorber
(c) adsorbent
(d) adsorbate

Question. Adsorption due to strong chemical forces is called
(a) Chemisorption
(b) Physisorption
(c) Reversible adsorption
(d) Both (b) and (c)

Question. Adsorption is always
(a) endothermic
(b) exothermic
(c) exothermic in case of physical and endothermic in case of chemical
(d) Either (a) or (b)

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

Question. Adsorption is accompanied by
(a) decrease in enthalpy and increase in entropy
(b) increase in enthalpy and increase in entropy
(c) decrease in enthalpy and decrease in entropy
(d) increase in enthalpy and decrease in entropy

Question. In physical adsorption, gas molecules are bound on the solid surface by
(a) chemical forces
(b) electrostatic forces
(c) gravitational forces
(d) van der Waal’s forces

Question. Extent of physisorption of a gas increases with _______.
(a) increase in temperature.
(b) decrease in temperature.
(c) decrease in surface area of adsorbent.
(d) decrease in strength of van der Waal’s forces.

Question. Extent of adsorption of adsorbate from solution phase increases with _________.
(a) increase in amount of adsorbate in solution. 
(b) decrease in surface area of adsorbent.
(c) increase in temperature of solution.
(d) decrease in amount of adsorbate in solution.

Question. Choose the incorrect statement in respect of physisorption?
(a) It is not specific in nature
(b) It arises because of van der Waal’s force
(c) It is reversible in nature
(d) Enthalpy of adsorption is in the range 80-240 kJ mol^–1

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       

Question. Methylene blue, from its aqueous solution, is adsorbed on activated charcoal at 25° C . For this process the correct statement is 
(a) the adso1ption requires activation at 25° C
(b) the adsorption is accompanied by a decrease in enthalpy
(c) the adsorption increases with increase of temperature
(d) the adso1ption is irreversible     

Question. The given graph/data I, II, III and IV represent general trends observed for different physisorption and chemisorption processes under mild conditions of temperature and pressure. Which of the following choice(s) about I, II, III and IV is (are) correct?    

(a) I is physisorption and II is chemisorption
(b) I is physisorption and III is chemisorption
(c) IV is chemisorption and II is chemisorption
(d) IV is chemisorption and III is chemisorption     

Question. Choose the correct reason(s) for the stability of the lyohobic colloidal particles. 
(a) Preferential adsorption of ions from the solution
(b) Preferential adsorption of solvent on their smface from the solution
(c) Attraction between different particles having opposite charges on their surface
(d) Potential difference between the fixed layer and the diffused layer of opposite charges around the
colloidal particles     

Question. According to Freundlich adsorption which of the following is correct? 
(a) x / m ∝ p⁰
(b) x / m ∝ p¹
(c) x / m ∝ p^1/n
(d) All of the above are correct for different range of pressure   

Question. During the adsorption of a gas on the surface of a solid, which of the following is true? 
(a) ΔG > 0, till< 0, ΔS < 0
(b) ΔG < 0, till< 0, ΔS < 0
(c) ΔG < 0, till< 0, ΔS > 0
(d) ΔG < 0, till> 0, ΔS < 0     

Question. For Freundlich isotherm, a graph of a log x/m is plotted against log p. The slope of the line and its y-axis intercept, respectively corresponds to 
(a) 1 / n , k
(b) log 1/n , k
(c) 1 / n, log k
(d) log 1 / n , log k     

Question. Assertion (A) van der Waals’ forces are responsible for chemisorption. Reason (R) High temperature is favourable for chemisorption. The correct answer is 
(a) A is incorrect but R is correct
(b) Both A and R are correct and R is the correct explanation of A
(c) Both A and R are correct and R is not the correct explanation of A
(d) A is correct but R is incorrect     

Question. During the adsorption of krypton on activated charcoal at low temperature 
(a) ΔH > 0 and ΔS < 0
(b) ΔH < 0 and ΔS < 0
(c) ΔH > 0 and ΔS > 0
(d) ΔH < 0 and ΔS > 0     

Question. In physical adsorption, the adsorbent and adsorbate are held together by the 
(a) ionic forces
(b) covalent forces
( c) van der Waals’ forces
(d) H-bonding     

Question. Which of the following is not a favourable condition for physical adsorption ?
(a) High pressure
(b) Negative ΔH
(c) Higher critical temperature of adsorbate
(d) High temperature

Question. The term ‘sorption’ stands for ___________.
(a) absorption
(b) adsorption
(c) both absorption and adsorption
(d) desorption

Question. In Freundlich adsorption isotherm, the value of 1/n is :
(a) between 0 and 1 in all cases
(b) between 2 and 4 in all cases
(c) 1 in case of physical adsorption
(d) 1 in case of chemisorption

Question. The role of a catalyst in a reversible reaction is to
(a) increase the rate of forward reaction
(b) decrease the rate of backward reaction
(c) alter the equilibrium constant of the reaction
(d) allow the equilibrium to be achieved quickly

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

Question. Physical adsorption of a gaseous species may change to chemical adsorption with ________.
(a) decrease in temperature 
(b) increase in temperature
(c) increase in surface area of adsorbent
(d) decrease in surface area of adsorbent

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

Question. According to Freundlich adsorption isotherm, the amount of gas adsorbed at very high pressure
(a) reaches a constant limiting value
(b) goes on increasing with pressure
(c) goes on decreasing with pressure
(d) increase first and decreases later with pressure

Question. In physisorption adsorbent does not show specificity for any particular gas because _________.
(a) involved van der Waal’s forces are universal.
(b) gases involved behave like ideal gases.
(c) enthalpy of adsorption is low.
(d) it is a reversible process.

Question. Catalyst increases the rate of reaction by
(a) decreasing threshold energy
(b) decreasing activation energy
(c) increasing activation energy
(d) decreasing equilibrium constant

Question. Catalytic poisons act by :
(a) making the products chemically inactive.
(b) increasing the rate of the backward reaction.
(c) chemical combination with any one of the reactants.
(d) preferential adsorption on the catalyst surface.

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

Question. A catalyst can affect reversible reaction by
(a) changing equilibrium constant
(b) slowing forward reaction
(c) attaining equilibria in both directions
(d) None of these

Question. Which is not correct regarding the adsorption of a gas on surface of solid?
(a) On increasing temperature, adsorption increases continuously
(b) Enthalpy and entropy changes are –ve
(c) Adsorption is more for some specific substance
(d) This Phenomenon is reversible

Question. Which one of the following is an example of homogeneous catalysis ?
(a) Haber’s process of synthesis of ammonia
(b) Catalytic conversion of SO₂ to SO₃ in contact process
(c) Catalytic hydrogenation of oils
(d) Acid hydrolysis of methyl acetate.

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

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

Question. What is the role of molybdenum in Haber’s process for manufacture of ammonia?
(a) As catalytic poison
(b) As a catalytic promoter
(c) As a catalyst
(d) As a reactant

Question. Milk is a colloid in which a
(a) liquid is dispersed in a liquid
(b) solid is dispersed in a liquid
(c) gas is dispersed in a liquid
(d) sugar is dispersed in a liquid

Question. An aerosol is a :
(a) dispersion of a solid or liquid in a gas
(b) dispersion of a solid in a liquid
(c) dispersion of a liquid in a liquid
(d) solid solution

Question. An example of dispersion of a liquid in a gas is :
(a) milk
(b) vegetable oil
(c) foam
(d) mist

Question. A biological catalyst is
(a) an enzyme
(b) a carbohydrate
(c) an amino acid
(d) a nitrogenous base

Question. The action of enzymes in living system is to :
(a) supply energy to tissues
(b) enhance immunity
(c) circulate oxygen
(d) enhance the rate of biochemical reactions.

Question. Butter is a colloid formed when
(a) Fat is dispersed in water
(b) Fat globules are dispersed in water
(c) Water is dispersed in fat
(d) None of the above

Question. Alloy is an example of
(a) gel
(b) solidified emulsion
(c) solid solution
(d) sol

Question. Hydrolysis of urea is an example of
(a) homogenous catalysis
(b) heterogenous catalysis
(c) biochemical catalysis
(d) zeolite catalysis

Question. Hair cream is an example of
(a) gel
(b) sol
(c) aerosol
(d) foam

Question. The efficiency of an enzyme in catalysing a reaction is due to its capacity
(a) to form a strong enzyme-substrate complex
(b) to decrease the bond energies of substrate molecule
(c) to change the shape of the substrate molecule
(d) to lower the activation energy of the reaction

Question. If dispersed phase is a liquid and the dispersion medium is a solid, the colloid is known as
(a) a sol
(b) a gel
(c) an emulsion
(d) a foam

Question. Which one of the following in not a colloidal solution?
(a) Smoke
(b) Ink
(c) Blood
(d) Air

Question. When dispersed phase is liquid and dispersion medium is gas then the colloidal system is called
(a) Smoke
(b) Clouds
(c) Jellies
(d) Emulsions

Question. Which one is a colloid?
(a) Sodium chloride
(b) Urea
(c) Cane sugar
(d) Blood

Question. Small liquid droplets dispersed in another liquid is called
(a) gel
(b) suspension
(c) emulsion
(d) true solution

Question. Suspensions are
(a) Visible to naked eye
(b) Not visible by any means
(c) Invisible under electron microscope
(d) Invisible through microscope

Question. Cloud or fog is an example of colloidal system of
(a) Liquid dispersed in gas
(b) Gas dispersed in gas
(c) Solid dispersed in gas
(d) Solid dispersed in liquid

Question. Cheese is an example of
(a) solid sol
(b) emulsion
(c) gel
(d) foam

Question. Which one of the following is correctly matched?
(a) Emulsion-smoke
(b) Gel-butter
(c) Aerosol-hair cream
(d) Sol-whipped cream

Question. A colloid always :
(a) Contains two phases
(b) Is a true solution
(c) Contains three phases
(d) Contains only water soluble particles

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