JEE Chemistry Surface Chemistry MCQs Set B

Question: Hydrolysis of urea is an example of

• a) biochemical catalysis
• b) homogenous catalysis
• c) heterogenous catalysis
• d) zeolite catalysis

Answer: biochemical catalysis

Question: The efficiency of an enzyme in catalysing a reaction is due to its capacity

• a) to lower the activation energy of the reaction
• b) to change the shape of the substrate molecule
• c) to decrease the bond energies of substrate molecule
• d) to form a strong enzyme-substrate complex

Answer: to lower the activation energy of the reaction

Question: What is the role of molybdenum in Haber’s process for manufacture of ammonia?

• a) As a catalytic promoter
• b) As a reactant
• c) As catalytic poison
• d) As a catalyst

Answer: As a catalytic promoter

Question: Which of the following step(s) is/are not involved in the mechanism of adsorption theory of heterogeneous catalyst?

(i) Diffusion of reactants to the surface of the catalyst.
(ii) Sorption of reactant molecules on the surface of the catalyst.
(iii) Occurrence of chemical reaction on the catalyst’s surface through formation of an intermediate.
(iv) Desorption of reaction products from the catalyst’s surface.
(v) Diffusion of reaction products away from the catalyst’s surface.

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

Answer: (ii) only

Question: Milk is a colloid in which a

• a) liquid is dispersed in a liquid
• b) solid is dispersed in a liquid
• c) sugar is dispersed in a liquid
• d) gas is dispersed in a liquid

Answer: liquid is dispersed in a liquid

Question: Butter is a colloid formed when

• a) Water is dispersed in fat
• b) None of the above
• c) Fat is dispersed in water
• d) Fat globules are dispersed in water

Answer: Water is dispersed in fat

Question: The size of colloidal particles is between

• a) 10^–5 – 10^–7 cm
• b) 10^–7 – 10^–9 cm
• c) 10^–9 – 10^–11 cm
• d) None of these

Answer: 10^–5 – 10^–7 cm

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

Answer: dispersion of a solid or liquid in a gas

Question: An example of dispersion of a liquid in a gas is

• a) mist
• b) vegetable oil
• c) milk
• d) foam

Answer: mist

Question: Alloy is an example of

• a) solid solution
• b) gel
• c) solidified emulsion
• d) sol

Answer: solid solution

Question: If dispersed phase is a liquid and the dispersion medium is a solid, the colloid is known as

• a) a gel
• b) a foam
• c) a sol
• d) an emulsion

Answer:  a gel

Question: Hair cream is an example of

• a) foam
• b) sol
• c) gel
• d) aerosol

Answer: foam

Question: Which one of the following is correctly matched?

• a) Gel-butter
• b) Sol-whipped cream
• c) Emulsion-smoke
• d) Aerosol-hair cream

Answer: Gel-butter

Question: Cheese is an example of

• a) gel
• b) solid sol
• c) emulsion
• d) foam

Answer: gel

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

Question: Which one of the following in not a colloidal solution?

• a) Air
• b) Ink
• c) Smoke
• d) Blood

Answer: Air

Question: Small liquid droplets dispersed in another liquid is called

• a) emulsion
• b) gel
• c) suspension
• d) true solution

Answer: emulsion

Question: When dispersed phase is liquid and dispersion medium is gas then the colloidal system is called

• a) Clouds
• b) Emulsions
• c) Smoke
• d) Jellies

Answer: Clouds

Question: Which one is a colloid?

• a) Blood
• b) Urea
• c) Sodium chloride
• d) Cane sugar

Answer: Blood

Question: Suspensions are

• a) Visible to naked eye
• b) Not visible by any means
• c) Invisible under electron microscope
• d) Invisible through microscope

Answer: Visible to naked eye

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

Answer: Liquid dispersed in gas

Question: A colloid always

• a) Contains two phases
• b) Is a true solution
• c) Contains three phases
• d) Contains only water soluble particles

Answer: Contains two phases

Question: Which one of the following is correctly matched ?

• a) Aerosol - smoke
• b) Emulsion - curd
• c) Foam - mist
• d) Solid sol - cake

Answer: Aerosol - smoke

Question: At the critical micelle concentration (CMC) the surfactant molecules

• a) associate
• b) dissociate
• c) decompose
• d) become completely soluble

Answer: associate

Question:  How non-polar and polar part in micelle are arranged ?

• a) Polar at outer surface and non-polar at inner surface
• b) Polar at inner surface and non-polar at outer surface
• c) Both polar and non-polar at inner surface
• d) Distributed all over the surface

Answer: Polar at outer surface and non-polar at inner surface

Question: Surface tension of lyophilic sols is

• a) lower than that of H₂O
• b) more than that of H₂O
• c) equal to that of H₂O
• d) None of these

Answer: lower than that of H₂O

Question: Which of the following is a lyophilic colloid ?

• a) Gum
• b) Blood
• c) Milk
• d) Fog

Answer: Gum

Question: Lyophobic colloids are

• a) irreversible colloids
• b) gun proteins
• c) protective colloids
• d) reversible colloids

Answer: irreversible colloids

Question: Which one is an example of multimolecular colloid system

• a) Gold dispersed in water
• b) Protein dispersed in water
• c) Soap dispersed in water
• d) Gum dispersed in water

Answer: Gold dispersed in water

Question: Example of intrinsic colloid is

• a) glue
• b) Fe
• c) sulphur
• d) None of these

Answer: glue

Question: Associated colloid among the following is

• a) sodium stearate
• b) proteins
• c) enzymes
• d) cellulose

Answer:  sodium stearate

Question: The formation of micelles takes place only above

• a) Kraft temperature
• b) critical temperature
• c) Boyle temperature
• d) inversion temperature

Answer: Kraft temperature

Question: A precipitate is changed to colloidal solution by the following process

• a) peptization
• b) dialysis
• c) ultrafiltration
• d) electrophoresis

Answer: peptization

Question: Which of the following is used for neutralising charge on colloidal solution?

• a) Electrolytes
• b) Electrons
• c) Positively charged ions
• d) Compounds

Answer: Electrolytes

Question: Pure water can be obtained from sea water by

• a) Reverse osmosis
• b) Centrifugation
• c) Plasmolysis
• d) Sedimentation

Answer: Reverse osmosis

Question: Blood may be purified by

• a) Dialysis
• b) Coagulation
• c) Electro-osmosis
• d) Filtration

Answer: Dialysis

Question: During dialysis

• a) solvent molecules and ions can diffuse
• b) all kinds of particles can diffuse through the semipermeable membrane
• c) solvent molecules, ions and colloidal particles can diffuse
• d) only solvent molecules can diffuse

Answer: solvent molecules and ions can diffuse

Question: The electrolytic impurities of a sol can most easily be separated by

• a) electrodialysis
• b) electrosmosis
• c) dialysis
• d) electrophoresis

Answer: electrodialysis

Question: The formation of colloid from suspension is

• a) Peptisation
• b) Sedimentation
• c) Condensation
• d) Fragmentation

Answer: Peptisation

Question: The separation of colloidal particles from particles of molecular dimensions is known as

• a) dialysis
• b) dispersion
• c) sedimentation
• d) pyrolysis

Answer: dialysis

Question: Which one of the following impurities present in colloidal solution cannot be removed by electrodialysis?

• a) Urea
• b) Sodium chloride
• c) Potassium sulphate
• d) Calcium chloride

Answer: Urea

Question: The migration of dispersion medium under the influence of an electric potential is called

• a) Electroosmosis
• b) Sedimentation
• c) Cataphoresis
• d) Electrophoresis

Answer: Electroosmosis

Question: The movement of colloidal particles towards their respective electrodes in the presence of an electric field is known as :

• a) electrophoresis
• b) Brownian movement
• c) electrolysis
• d) electrodialysis

Answer: electrophoresis

Question:  Peptization denotes

• a) Breaking and dispersion into the colloidal state
• b) Precipitation of solid from colloidal dispersion
• c) Hydrolysis of proteins
• d) Digestion of food

Answer: Breaking and dispersion into the colloidal state

Question: Colloidal gold is prepared by

• a) Bredig’s Arc method
• b) Mechanical dispersion
• c) Peptisation
• d) Hydrolysis

Answer: Bredig’s Arc method

Question: Peptization involves

• a) disintegration of colloidal aggregates
• b) evaporation of dispersion medium
• c) impact of molecules of the dispersion medium on the colloidal particles
• d) precipitation of colloidal particles

Answer: disintegration of colloidal aggregates

Question: Hardy-Schulze rule explains the effect of electrolytes on the coagulation of colloidal solution. According to this rule, coagulation power of cations follow the order

• a) Al⁺³ > Ba⁺² > Na⁺
• b) Ba⁺² > N^a+ > Al⁺³
• c) Both
• d) None of these

Answer: Al⁺³ > Ba⁺² > Na⁺

Question: Tyndall effect is shown by

• a) sol
• b) solution
• c) precipitate
• d) plasma

Answer: sol

Question: The cause of Brownian movement is

• a) the impact of molecules of the dispersion medium on the colloidal particles
• b) attractive forces between the colloidal particles and molecules of dispersion medium
• c) convectional currents
• d) heat changes in liquid state

Answer: the impact of molecules of the dispersion medium on the colloidal particles

Question: When a strong beam of light is passed through a colloidal solution, the light will

• a) be scattered
• b) give a rainbow
• c) be reflected
• d) be refracted

Answer: be scattered

Question: The simplest way to check whether a system is colloidal or not is by

• a) Tyndall effect
• b) Electrodialysis
• c) Brownian movement
• d) Measuring particle size

Answer: Tyndall effect

Question: The ability of an ion to bring about coagulation of a given colloid depends upon

• a) both magnitude and sign of its charge
• b) the sign of its charge
• c) the magnitude of its charge
• d) its size

Answer: both magnitude and sign of its charge

Question: Which of the following electrolytes is least effective in coagulating ferric hydroxide solution?

• a) KBr
• b) K₂SO₄
• c) K₂CrO₄
• d) None of these

Answer: KBr

Question: Which of the following acts as protective colloid

• a) Gelatin
• b) Silica gel
• c) Sodium acetate
• d) None of these

Answer: Gelatin

Question:  Tyndall effect shown by colloids is due to

• a) scattering of light by the particles
• b) None of these
• c) reflection of light by the particles
• d) coagulation of particles

Answer: scattering of light by the particles

Question: Which of the following is not a property of colloidal solution?

• a) Particle size > 100 nm
• b) Heterogenity
• c) Brownian movement
• d) None of these

Answer: Particle size > 100 nm

Question: Which of the following is most powerful to coagulate the negative colloid?

• a) AlCl₃
• b) ZnSO₄
• c) Na₃PO₄
• d) None of these

Answer:  AlCl₃

Question: The charge on colloidal particles is due to

• a) adsorption of ions from the solution
• b) very small size of particles
• c) presence of electrolyte
• d) None of these

Answer: adsorption of ions from the solution

Question: The ion that is more effective for the coagulation of As₂S₃ sol is

• a) AI³⁺
• b) Na⁺
• c) Ba²⁺
• d) None of these

Answer: AI³⁺