JEE Chemistry Surface Chemistry MCQs Set A

Question: Adsorbed acetic acid on activated charcoal is

• a) adsorbate
• b) absorber
• c) adsorber
• d) adsorbent

Answer: adsorbate

Question: Adsorption is always

• a) exothermic
• b) endothermic
• c) exothermic in case of physical and endothermic in case of chemical
• d) None of these

Answer: exothermic

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

Answer: On increasing temperature, adsorption increases continuously

Question: How many layers are adsorbed in chemical adsorption ?

• a) One
• b) Two
• c) Many
• d) Zero

Answer: One

Question: Adsorption due to strong chemical forces is called

• a) Chemisorption
• b) Physisorption
• c) Reversible adsorption
• d) None of these

Answer: Chemisorption

Question: In physical adsorption, gas molecules are bound on the solid surface by

• a) van der Waal’s forces
• b) electrostatic forces
• c) chemical forces
• d) gravitational forces

Answer: van der Waal’s forces

Question: Which of the following statements is not correct

• a) Chemical adsorption first decreases with increase in temperature
• b) Physical adsorption is due to van der Waal’s forces
• c) Physical adsorption is reversible
• d) Adsorption energy for a chemical adsorption is generally greater than that of physical adsorption

Answer:  Chemical adsorption first decreases with increase in temperature

Question: Adsorption of gases on solid surface is exothermic reaction because

• a) enthalpy is negative
• b) enthalpy is positive
• c) free energy increases
• d) entropy increases

Answer: enthalpy is negative

Question: The gas which is least adsorbed on charcoal (under identical conditions) is

• a) O₂
• b) NH₃
• c) HCl
• d) CO₂

Answer: O₂

Question: Adsorption is accompanied by

• a) decrease in enthalpy and decrease in entropy
• b) increase in enthalpy and increase in entropy
• c) decrease in enthalpy and increase in entropy
• d) increase in enthalpy and decrease in entropy

Answer: decrease in enthalpy and decrease in entropy

Question: Choose the incorrect statement in respect of physisorption?

• a) Enthalpy of adsorption is in the range 80-240 kJ mol^–1
• b) It is reversible in nature
• c) It arises because of van der Waal’s force
• d) It is not specific in nature

Answer: Enthalpy of adsorption is in the range 80-240 kJ mol^–1

Question: The term ‘sorption’ stands for ___________.

• a) both absorption and adsorption
• b) desorption
• c) adsorption
• d) absorption

Answer: both absorption and adsorption

More Questions.............................................

Question: Extent of physisorption of a gas increases with

• a) decrease in temperature
• b) increase in temperature
• c) decrease in surface area of adsorbent.
• d) decrease in strength of van der Waal’s forces

Answer: decrease in temperature

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

Answer: increase in amount of adsorbate in solution.

Question: Which of the following is not a favourable condition for physical adsorption ?

• a) High temperature
• b) Higher critical temperature of adsorbate
• c) High pressure
• d) None of these

Answer: High temperature

Question: Physical adsorption of a gaseous species may change to chemical adsorption with ________.

• a) increase in temperature
• b) decrease in temperature
• c) increase in surface area of adsorbent
• d) decrease in surface area of adsorbent

Answer: increase in temperature

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

Answer: involved van der Waal’s forces are universal

Question: Which of the following is an example of absorption

• a) Water on calcium chloride.
• b) Water on silica gel
• c) Hydrogen on finely divided nickel
• d) Oxygen on metal surface

Answer: Water on calcium chloride.

Question: For adsorption of a gas on a solid, the plot of log x/m vs log P is linear with slope equal to (n being whole number)

• a)

  

• b) log k
• c) k
• d) n

Answer:

Question: The adsorption of a gas on a solid surface varies with pressure of the gas in which of the following manner

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: If x is amount of adsorbate and m is amount of adsorbent, which of the following relations is not related to adsorption process ?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

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

Answer: between 0 and 1 in all cases

Question: Which is adsorbed in maximum amount by activated charcoal ?

• a) CO₂
• b) O₂
• c) N₂
• d) Cl₂

Answer: CO₂

Question:  Freundlich equation for adsorption of gases (in amount of x g) on a solid (in amount of m g) at constant temperature can be expressed as

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

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) increase first and decreases later with pressure
• d) None of these

Answer: reaches a constant limiting value

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

Answer: On increasing temperature, adsorption increases continuously

Question: Which of the following curves is in accordance with Freundlich adsorption isotherm ?

• a) 

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:

• a) (i), (ii) and (iv)
• b) (iii) only
• c) (ii) and (iii)
• d) (i), (iii) and (iv)

Answer: (i), (ii) and (iv)

Question: The role of a catalyst in a reversible reaction is to

• a) allow the equilibrium to be achieved quickly
• b) alter the equilibrium constant of the reaction
• c) decrease the rate of backward reaction
• d) increase the rate of forward reaction

Answer: allow the equilibrium to be achieved quickly

Question:  Catalytic poisons act by

• a) preferential adsorption on the catalyst surface
• b) chemical combination with any one of the reactants.
• c) increasing the rate of the backward reaction
• d) making the products chemically inactive

Answer: preferential adsorption on the catalyst surface

Question: A catalyst

• a) lowers the activation energy
• b) changes the rate constant
• c) changes the product
• d) itself destroyed in the reaction

Answer: lowers the activation energy

Question: Active charcoal is a good catalyst because it

• a) has more adsorption power
• b) has inert nature toward reagents
• c) is very reactive.
• d) is made up of carbon atoms

Answer: has more adsorption power

Question: Which of the following kind of catalysis can be explained by the adsorption theory ?

• a) Heterogeneous catalysis
• b) Enzyme catalysis
• c) Acid - base catalysis
• d) Homogeneous catalysis

Answer: Heterogeneous catalysis

Question: According to the adsorption theory of catalysis, the speed of the reaction increases because-

• a) Adsorption lowers the activation energy of the reaction
• b) The concentration of reactant molecules at the active centres of the catalyst becomes high due to strong adsorption
• c) In the process of adsorption, the activation energy of the molecules becomes large
• d) Adsorption produces heat which increases the speed of the reaction

Answer: Adsorption lowers the activation energy of the reaction

Question: Catalyst increases the rate of reaction by

• a) decreasing activation energy
• b) increasing activation energy
• c) decreasing equilibrium constant
• d) decreasing threshold energy

Answer: decreasing activation energy

Question: A catalyst can affect reversible reaction by

• a) attaining equilibria in both directions
• b) None of these
• c) slowing forward reaction
• d) changing equilibrium constant

Answer: attaining equilibria in both directions

Question: Which one of the following is an example of homogeneous catalysis

• a) Acid hydrolysis of methyl acetate
• b) Catalytic hydrogenation of oils
• c) Haber’s process of synthesis of ammonia
• d) None of these

Answer: Acid hydrolysis of methyl acetate

Question: Identify the correct statement regarding enzymes

• a) Enzymes are specific biological catalysts that possess well-defined active sites
• b) Enzymes are normally heterogeneous catalysts that are very specific in their action
• c) Enzymes are specific biological catalysts that cannot be poisoned
• d) None of these

Answer: Enzymes are specific biological catalysts that possess well-defined active sites

Question: A biological catalyst is

• a) an enzyme
• b) an amino acid
• c) a carbohydrate
• d) a nitrogenous base

Answer: an enzyme

Question: The action of enzymes in living system is to

• a) enhance the rate of biochemical reactions
• b) circulate oxygen
• c) enhance immunity
• d) supply energy to tissues

Answer: enhance the rate of biochemical reactions

Question: In petrochemical industry alcohols are directly converted to gasoline by passing over heated

• a) ZSM-5
• b) Nickel
• c) Platinum
• d) Iron

Answer: ZSM-5

Question:

• a) Selectivity
• b) Activity
• c) Catalytic promoter
• d) Catalytic poison

Answer: Selectivity

Question: The dispersed phase and dispersion medium in soap lather are respectively

• a) gas and liquid
• b) solid and gas
• c) liquid and gas
• d) solid and liquid

Answer: gas and liquid

Question: Which of the following is not a colloid ?

• a) Chlorophyll
• b) Ruby glass
• c) Smoke
• d) Milk

Answer: Chlorophyll

Question: Which of the following forms a colloidal solution in water ?

• a) Starch
• b) NaCl
• c) Glucose
• d) Barium nitrate

Answer:  Starch

Question: Which of the following forms cationic micelles above certain concentration?

• a) Cetyl trimethyl ammonium bromide
• b) Urea
• c) Sodium acetate
• d) Sodium dodecyl sulphate

Answer: Cetyl trimethyl ammonium bromide

Question: Which of the following does not contain a hydrophobic structure ?

• a) Rubber
• b) Lanolin
• c) Linseed oil
• d) Glycogen

Answer: Rubber

Question: Which one of the following is an example for multimolecular colloid?

• a) Aqueous starch sol
• b) Aqueous enzyme sol
• c) Alcoholic polystyrene sol
• d) Aqueous sol of sodium laurylsulphate

Answer: Aqueous starch sol

Question:  Bredig arc method cannot be used to prepare colloidal solution of which of the following

• a) Fe
• b) Au
• c) Pt
• d) Ag

Answer: Fe

Question: Colloidal solutions are not purified by

• a) Electrophoresis
• b) Electrodialysis
• c) Ultrafiltration
• d) Dialysis

Answer: Electrophoresis

Question: Colloid of which one of the following can be prepared by electrical dispersion method as well as reduction method ?

• a) Gold
• b) Ferric hydroxide
• c) Sulphur
• d) Arsenious sulphide

Answer: Gold

Question: Which of the following ions can cause coagulation of proteins ?

• a) Ag⁺
• b) Mg²⁺
• c) Na⁺
• d) Ca²⁺

Answer: Ag⁺

Question:  Which of the following will be most effective in the coagulation of Al(OH)₃ sol ?

• a) Mg₃(PO₄)₂
• b) BaCl₂
• c) KCN
• d) NaCl

Answer: Mg₃(PO₄)₂

Question: The disperse phase in colloidal iron (III) hydroxide and colloidal gold is positively and negatively charged, respectively. Which of the following statements is NOT correct?

• a) Mixing the sols has no effect
• b) Coagulation in both sols can be brought about by electrophoresis
• c) Sodium sulphate solution causes coagulation in both sols
• d) Magnesium chloride solution coagulates, the gold sol more readily than the iron (III) hydroxide sol.

Answer: Mixing the sols has no effect

Question: Point out the false statement

• a) The colloidal solution of a liquid in liquid is called gel
• b) Hardy Schulze rule is related with coagulation
• c) Brownian movement and Tyndall effect are shown by colloidal system
• d) Gold number is a measure of the protective power of lyophilic colloid

Answer: The colloidal solution of a liquid in liquid is called gel

Question: A colloidal solution is subjected to an electric field. The particles move towards anode. The coagulation of same sol is studied using NaCl, BaCl₂ and AlCl₃ solutions. The order of their coagulation power should be –

• a) AlCl₃ > BaCl₂ > NaCl
• b) NaCl > BaCl₂ > AlCl₃
• c) BaCl₂ > AlCl₃ > NaCl
• d) None of these

Answer: AlCl₃ > BaCl₂ > NaCl

Question: Flocculation value of BaCl₂ is much less than that of KCl for sol A and flocculation value of Na₂SO₄ is much less than that of NaBr for sol B. The correct statement among the following is

• a) Sol A is positively charged arid Sol B is negatively charged
• b) Both the sols A and B are positively charged
• c) Sol A is negatively charged and sol B is positively charged
• d) Both the sols A and B are negatively charged

Answer: Sol A is positively charged arid Sol B is negatively charged

Question: In Brownian movement or motion, the paths of the particles are

• a) Zig-zag
• b) Curved
• c) Linear
• d) Uncertain

Answer: Zig-zag

Question: How does a delta form at the meeting place of sea and river water?

• a) The electrolyte present in sea water coagulate the clay
• b) the electrolyte present in sea water has no role
• c) the electrolyte present in river water coagulate the clay
• d) None of these

Answer: The electrolyte present in sea water coagulate the clay

Question:  _______ is a silver sol used as an eye lotion. Fill in the blank with an appropriate answer.

• a) Amytol
• b) Argyrol
• c) Ciprofloxacin
• d) None of these

Answer: Amytol

Question: Which of the following will show Tyndall effect?

• a) Aqueous solution of soap above critical micelle concentration
• b) Aqueous solution of sodium chloride
• c) Aqueous solution of sugar
• d) Aqueous solution of soap below critical micelle concentration

Answer: Aqueous solution of soap above critical micelle concentration

Question: Which of the following combinations of dispersed phase and dispersion medium will not form a colloid ?

• a) Dispersed phase – Gas, Dispersion medium – Gas
• b) Dispersed phase – Solid, Dispersion medium – Gas
• c) Dispersed phase – Solid, Dispersion medium – Solid
• d) None of these

Answer: Dispersed phase – Gas, Dispersion medium – Gas

Question: Which of the following statements is incorrect?

• a) Tannin used in leather industry contains positively charged colloidal particles
• b) Photographic films are prepared by coating an emulsion of AgBr in gelatin over glass plate
• c) Colloidal solution of latex is used in preparation of rubber
• d) Colloidal gold is used for intramuscular injection

Answer: Tannin used in leather industry contains positively charged colloidal particles

Question: Which of the following is not correctly matched

• a) Gold sol – Double decomposition
• b) Sulphur sol – Oxidation
• c) Fe(OH)₃ sol – Hydrolysis
• d) None of these

Answer: Gold sol – Double decomposition

Question:

• a) 4
• b) All of these
• c) 3
• d) 6

Answer: 4