We have compiled the NCERT MCQ Questions for Class 12 Chemistry Chapter 5 Surface Chemistry with Answers Pdf free download covering the entire syllabus. Practice MCQ Questions for Class 12 Chemistry with Answers on a daily basis and score well in exams. Refer to the Surface Chemistry Class 12 MCQs Questions with Answers here along with a detailed explanation.
Surface Chemistry Class 12 MCQs Questions with Answers
Question 1.
Cottrell smoke precipitator works on the principle of:
(a) Distribution
(b) neutralisation of charge on colloids
(c) Le-chatelier’s principle
(d) Addition of electrolytes.
Answer
Answer: (b) neutralisation of charge on colloids
Question 2.
Which of the following is a lyophobic colloid?
(a) gelatin
(b) sulphur
(c) starch
(d) gum arabic.
Answer
Answer: (b) sulphur
Question 3.
The nature of bonding forces in adsorption are
(a) purely physical such as Van der Waal’s forces
(b) purely chemical
(c) both chemical and physical
(d) sometimes physical and sometimes chemical.
Answer
Answer: (c) both chemical and physical
Question 4.
The protective power of a lyophilic sol is
(a) defined by Hardy-Schulze rule
(b) proportional to the quantity of electrical charge on it
(c) measured in terms of gold number
(d) determined by the size of its colloidal particles.
Answer
Answer: (c) measured in terms of gold number
Question 5.
The Tyndall effect associated with colloidal particles is due to
(a) presence of electrical
(b) scattering of light charge
(c) absorption of light
(d) reflection of light
Answer
Answer: (c) absorption of light
Question 6.
Which one of the following is not applicable to chemisorption?
(a) Its heat of adsorption is high
(b) It takes place at high temperature
(c) It is reversible
(d) It forms mono-molerular layers.
Answer
Answer: (c) It is reversible
Question 7.
In the colloidal state the particle size ranges
(a) below 1 nm
(b) between 1 nm to 100 nm
(c) more than 100 nm
(d) none of the above.
Answer
Answer: (b) between 1 nm to 100 nm
Question 8.
All colloids
(a) are suspension of one phase in another
(b) are two-phase systems
(c) contain only water-soluble particles
(d) are true solutions.
Answer
Answer: (b) are two-phase systems
Question 9.
Colloids can be purified by
(a) condensation
(b) peptization
(c) coagulation
(d) dialysis.
Answer
Answer: (d) dialysis.
Question 10.
Milk is an example of
(a) emulsion
(b) suspension
(c) foam
(d) sol.
Answer
Answer: (a) emulsion
Question 11.
Colloidal particles in a sol can be coagulated by
(a) heating
(b) adding an electrolyte
(c) adding oppositely charge sol
(d) any of the above methods
Answer
Answer: (d) any of the above methods
Question 12.
Emulsifier is an agent which
(a) accelerates the dispersion
(b) homogenizes an emulsion
(c) stabilizes an emulsion
(d) aids the flocculation of an emulsion.
Answer
Answer: (c) stabilizes an emulsion
Question 13.
Fog is colloidal system of
(a) gas in liquid
(b) liquid in gas
(c) gas in gas
(d) gas in solid.
Answer
Answer: (b) liquid in gas
Question 14.
Given below are a few electrolytes, indicate which one among them will bring about the coagulation of a gold sol quickest and in the least of concentration?
(a) NaCl
(b) MgSO4
(c) Al2(SO4)3
(d) K4[Fe(CN)6]
Answer
Answer: (c) Al2(SO4)3
Question 15.
Milk is an emulsion of fat, etc., dispersed in
(a) water
(b) amino acid
(c) fatty acid
(d) saline water.
Answer
Answer: (a) water
Question 16.
When a colloidal solution is observed under ultramicroscope, we can see
(a) light scattered by colloidal particles
(b) size of the colloidal particles
(c) shape of the colloidal particles
(d) relative size of the colloidal particles
Answer
Answer: (a) light scattered by colloidal particles
Question 17.
Colloidal solutions are classified on the basis of:
(a) molecular size
(b) organic or inorganic
(c) surface tension value
(d) pH value.
Answer
Answer: (a) molecular size
Question 18.
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.
Answer
Answer: (a) lower than that of H2O
Question 19.
Colloidal sol is:
(a) true solution
(b) suspension
(c) heterogeneous sol
(d) homogeneous sol.
Answer
Answer: (c) heterogeneous sol
Question 20.
Blood may be purified by:
(a) Dialysis
(b) electro-osmosis
(c) coagulation
(d) Alteration.
Answer
Answer: (a) Dialysis
Question 21.
Which of the following characteristics is not correct for physical adsorption?
(a) Adsorption increases with increase in temperature.
(b) Adsorption is spontaneous
(c) Both enthalpy and entropy of adsorption are negative
(d) Adsorption on solids is reversible.
Answer
Answer: (a) Adsorption increases with increase in temperature.
Question 22.
A colloidal system in which gas bubbles are dispersed in a liquid is known as:
(a) foam
(b) aerosol
(c) sol
(d) emulsion.
Answer
Answer: (a) foam
Question 23.
Which one of the following forms micelles in aqueous solution above certain concentration?
(a) Glucose
(b) Urea
(c) Dodecyl trimethyl ammonium chloride
(d) Pyridinium chloride
Answer
Answer: (c) Dodecyl trimethyl ammonium chloride
Question 24.
Adsorption of gases on solid surface is generally exothermic because
(a) enthalpy is positive
(b) entropy decreases
(c) entropy increases
(d) free energy increases.
Answer
Answer: (b) entropy decreases
Question 25.
Identify the gas which is readily adsorbed by activated charcoal.
(a) N2
(b) SO2
(c) H2
(d) O2
Answer
Answer: (b) SO2
Question 26.
In coagulating the colloidal solution of AS2S3, which has the minimum coagulating value?
(a) NaCl
(b) KCl
(c) BaCl2
(d) AICl3
Answer
Answer: (d) AICl3
Question 27.
Which of the following forms cationic micelles above certain concentration?
(a) sodium dodecyl sulphate
(b) sodium acetate
(c) urea
(d) cetyl trimethyl ammonium bromide.
Answer
Answer: (d) cetyl trimethyl ammonium bromide.
Question 28.
Which one of the following statements about the zeolites is false?
(a) They are used as cation exchangers
(b) They have open structure which enables them to take up small molecules.
(c) Zeolites are alumino silicates having three dimensional network.
(d) Some of the SiO44- units are replaced by AlO45- and AlO69- ions is zeolites.
Answer
Answer: (d) Some of the SiO44- units are replaced by AlO45- and AlO69- ions is zeolites.
Question 29.
Bredig arc method cannot be used to prepare colloidal solution of whichof the following?
(a) Pt
(b) Fe
(c) Ag
(d) Au
Answer
Answer: (b) Fe
Question 30.
The dispersed phase in colloidal iron (III) hydroxide and colloidal gold is positively and negatively charged respectively. Which of the following statements is not correct?
(a) Magnesium chloride solution coagulates the gold sol more readily than the iron (III) hydroxide sol
(b) Sodium sulphate solution causes coagulation in both sols.
(c) Mixing the sols has no effect
(d) Coagulation of both sols can be brought about by electrophoresis.
Answer
Answer: (c) Mixing the sols has no effect
Question 31.
Which of the following is correct about lyophilic sols?
(a) They are irreversible
(b) They are formed by inorganic substance
(c) They are readily coagulated by addition of electrolytes
(d) They are self-stabilized.
Answer
Answer: (c) They are readily coagulated by addition of electrolytes
Question 32.
The volume of a colloidal particle, Vc as compared to the volume of a solute particle in a true solution Vs, could be
(a) \(\frac {V_C}{V_S}\) ≈ 1
(b) \(\frac {V_C}{V_S}\) ≈ 1023
(c) \(\frac {V_C}{V_S}\) ≈ 10-3
(d) \(\frac {V_C}{V_S}\) ≈ 103
Answer
Answer: (d) \(\frac {V_C}{V_S}\) ≈ 103
Question 33.
Which one of the following is correctly matched?
(a) Emulsion-curd
(b) Foam-mist
(c) Aerosol-smoke
(d) Solid sol-cake.
Answer
Answer: (c) Aerosol-smoke
Question 34.
Cellulose dispersed in ethanol is called:
(a) Emulsion
(b) Micelle
(c) Collodion
(d) Hydrophilic sol.
Answer
Answer: (c) Collodion
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