Chapter-5 Surface Chemistry MCQs
Q 1.: The presence of electric charge on the colloidal particle is indicated by the experiment
(A) Dialysis
(B) Osmosis
(C) Electrophoresis
(D) Electrolysis
Option – C
Q 2.: 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
Option – B
Q 3.:Which of the following electrolyte will have maximum flocculation value for Fe(OH)3 sol ?
(A) NaCl
(B) Na2S
(C) (NH4)3PO4
(D) K2SO4
Option – A
Q 4.:Which one of the following is not explained by adsorption ?
(A) When acetic acid solution is shaken with charcoal, the concentration of the acid decreases.
(B) The white precipitate of Mg(OH)2 attains blue colour when precipitated in the presence of magneson reagent
(C) An aqueous solution of NaOH attains pink colour with a drop of phenolphthalein
(D) The air becomes dry in the presence of silica gel.
Option – C
Q 5.:Which of the following statement is incorrect for physical adsorption ?
(A) It is instantaneous.
(B) Monomolecular layer forms on the adsorbent
(C) Less activation energy is required for it
(D) Generally it results at low temperature and adsorption decreases with increase in temperature
Option – B
Q 6.: In Freundlich adsorption isotherm the value of yn 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
Option – A
Q 7.: Adsorption is accompanied by the evolution of heat, so according to Le-chatelier’s principle, the amount of substance absorption should
(A) increase with increase in temperature
(B) decrease with decrease in temperature
(C) increase with decrease in temperature
(D) None of these
Option – C
Q 8.: Which of the following is a wrong statement for physisorption ?
(A) It is a reversible reaction
(B) The value of absorption enthalpy is low
(C) It is generally occurring at low temperature
(D) Reaction requires an activation energy
Option – D
Q 9.: Pieces of wood burn faster than a log of wood of the same mass because
(A) Surface area of log of wood is larger and needs more time to burn
(B) Pieces of wood have large surface area
(C) All pieces of wood catch fire at the same time
(D) Block of wood has higher density than pieces of the same wood
Option – B
Q 10.: Which among the following statement is false.:
(A) The adsorption may be mono-layered or multi-layered
(B) Increase of pressure increases amount of adsorption
(C) Particle size of adsorbent will not affect the amount of adsorption
(D) All of the above
Option – C
Q 11.: The gas that is adsorbed to a large extent on charcoal is
(A) H2
(B) CO
(C) CO2
(D) NH3
Option – D
Q 12.: The Langmuir adsorption isotherm is deduced using the assumption
(A) The adsorption takes place in multilayers
(B) The adsorption sites are equivalent in their ability to adsorb the particles
(C) The heat of adsorption varies with coverage
(D) The adsorbed molecules interact with each other
Option – A
Q 13.: Select the incorrect statement.
(A) Physical adsorption is reversible while chemical is irreversible
(B) High pressure favours physical adsorption while low pressure favours chemical adsorption
(C) Physical adsorption is not specific while chemical is highly specific
(D) High activation energy is involved in chemical adsorption
Option – B
Q 14.: According to the adsorption theory of catalysis the speed of reaction increases because
(A) Adsorption produces heat which increases the speed of 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 absorption
(D) In the process of adsorption, the activation energy of the molecules large
Option – A
Q 15.: Which one of the following is an example for homogeneous catalysis
(A) Manufacturing of sulphuric acid by contact process
(B) Manufacturing of ammonia by Haber process
(C) Hydrolysis of sugar in the presence of dilute hydrochloric acid
(D) Hydrogenation of oil
Option – C
Q 16.: What is the role of a catalyst in a reaction ?
(A) Affects the enthalpy change
(B) Affects the free energy change
(C) Increase the activation energy
(D) Lowers the activation energy
Option – D
Q 17.: Catalytic poisons act by
(A) Making the products chemically inactive
(B) Increasing the rate of the backward reactions
(C) Chemical combination with any one of the reactants
(D) Preferential adsorption on the catalyst surface
Option – D
Q 18.: Shape-selective-catalysis is a reaction catalysed by
(A) Platinum
(B) Zeolites
(C) Ziegler-natta catalyst
(D) Enzymes
Option – B
Q 19.: Adsorption of gases on solid surface is exothermic since
(A) Entropy is decreases
(B) Entropy is increases
(C) Free energy increases
(D) Enthalpy is positive
Option – A
Q 20.: Stability of lyophilic colloids is due to
(A) same charge on all the colloidal particles
(B) solvation of the colloidal particles
(C) both ‘A’ and ‘B’
(D) the fact that they are organic substances
Option – C
Q 21.: Which of the following statements is correct for the spontaneous adsorption of a gas ?
(A) ΔS is negative and, therefore ΔH should be highly positive
(B) ΔS is negative and, therefore ΔH should be highly negative
(C) ΔS is positive and, therefore ΔH should be highly positive
(D) ΔS is positive and, therefore ΔH should be highly negative
Option – B
Q 22.: Which of the following process is responsible for the formation of delta at a place where rivers meet the sea ?
(A) Peptization
(B) Coagulation
(C) Colloid formation
(D) Emulsification
Option – B
Q 23.: Which property of colloids is not depend on the charge on colloidal particles ?
(A) Coagulation
(B) Electrophoresis
(C) Electro-osmosis
(D) Tyndall effect
Option – D
Q 24.: At high concentration of soap in water, soap behaves as ……….
(A) Associated colloid
(B) Multimolecular colloid
(C) Macromolecular colloid
(D) Lyophobic colloid
Option – A
Q 25.: Which one of the following has minimum gold number ?
(A) Starch
(B) Gum arabic
(C) Sodium oleate
(D) Gelatin
Option – D
Q 26.: Which one of the following does not involve coagulation ?
(A) Formation of delta region
(B) Petptization
(C) Treatment of drinking water by potash alum
(D) Clotting of blood by the use of ferric chloride
Option – B
Q 27.: Which of the following process is not responsible for the presence of electric charge on the sol particles ?
(A) Electron capture by sol particles
(B) Adsorption of ionic species from solution
(C) Absorption of ionic species from solution
(D) Formation of helmholtz electrical double layer
Option – C
Q 28.: Decomposition of hydrogen peroxide can be prevented in presence of
(A) Glycerol
(B) Acetanilide
(C) Phosphoric acid
(D) All of these
Option – D
Q 29.: Intensity of the scattered light depends upon the difference of which of the following property of the dispersed phase and the dispersion medium ?
(A) Density
(B) Refractive index
(C) Viscosity
(D) Surface tension
Option – B
Q 30.: Tanning of leather is
(A) Colouring of leather by chemicals
(B) Drying process to make the leather hard
(C) Polishing of leather
(D) Hardening of leather by coagulation
Option – D
Q 31.: Gelatine is mostly used in making ice-creams in order to
(A) Prevent crystallisation and stabilise the mix
(B) Prevent forming the colloidal sol
(C) Modify the taste
(D) Enrich the fragrance
Option – A
Q 32.: Which of the following process does not occur at the interface of phases ?
(A) Crystallisation
(B) Homogenous catalysis
(C) Heterogenous catalysis
(D) Corrosion
Option – B
Q 33.: Which of the following does not form a lyophilic colloid ?
(A) Rubber dissolved in benzene
(B) White of the egg dissolved into water
(C) Common salt added to benzene
(D) Stannous chloride solution added to gold chloride solution
Option – D
Q 34.: Which of the following is correct ?
(A) Adsorption is always exothermic
(B) Adsorption is always endothermic
(C) Physical adsorption is endothermic whereas chemisorption is exothermic
(D) Physical adsorption is exothermic whereas chemisorption is endothermic
Option – A
Q 35.: What happens when blood charcoal is stirred in a solution of KCl ?
(A) Dilute KCl solution shows no adsorption whereas concentrated KCl shows adsorption
(B) Concentrated KCl solution shows no adsorption whereas dilute KCl shows adsorption
(C) Dilute KCl solution shows positive adsorption whereas concentrated KCl solution shows negative adsorption
(D) Concentrated KCl solution shows positive adsorption whereas dilute KCl solution shows negative adsorption
Option – D
Q 36.: An example of autocatalysis is
(A) Oxidation of NO to NO2
(B) Oxidation of SO2 and SO3
(C) Decomposition of KClO3 to KCl and O2
(D) Oxidation of oxalic acid by acidified KMnO4
Option – D
Q 37.: 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 prolonged dialysis
Option – C
Q 38.: 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 sodium chloride
(D) Aqueous solution of sugar
Option – A
Q 39.: On addition of one mL solution of 10% NaCl to 10 mL gold sol in the presence of 0.0250 gm of starch, the coagulation is just prevented. Starch has the following gold number :
(A) 0.025
(B) 0.25
(C) 2.5
(D) 25.0
Option – D
Q 40.: The coagulation of 200 mL of a positive colloid took place when 0.73 gm HCl was added to it without changing the volume much. The coagulating value of HCl for the colloid is
(A) 150
(B) 100
(C) 73
(D) 60
Option – B