CBSE Class 12 Chemistry Surface Chemistry MCQs Set B

Question. Which one of the following characteristics is associated with adsorption?
(a) DG and DH are negative but DS is positive.
(b) DG and DS are negative but DH is positive.
(c) DG is negative but DH and DS are positive.
(d) DG, DH and DS all are negative.

Answer : D

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 absorption
(d) 1 in case of chemisorption.

Answer : A

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) x/m = f (p) at constant T
(b) x/m = f (T) at constant p
(c) p = f (T) at constant (x/m)
(d) x/m = p ×T

Answer : D

Question. The Langmuir adsorption isotherm is deduced using the assumption
(a) the adsorption sites are equivalent in their ability to adsorb the particles
(b) the heat of adsorption varies with coverage
(c) the adsorbed molecules interact with each other
(d) the adsorption takes place in multilayers.

Answer : A

Question. A plot of log(x/m) versus log P for the adsorption of a gas on a solid gives a straight line with slope equal to
(a) log k
(b) –log k
(c) n
(d) 1/n

Answer : D

Question. When a few typical solutes are separated by a particular selective membrane such as protein particles, blood corpuscles, this process is called
(a) transpiration
(b) endosmosis
(c) dialysis
(d) diffusion

Answer : C

Question. Preparation of Lyophobic sols by chemical method involves
(a) double decomposition
(b) oxidation & reduction
(c) hydrolysis
(d) all of the options

Answer : D

Question. A colloidal solution is subjected to an electrical field. The particles move towards anode. The coagulation of same sol is studied using NaCl, BaCl₂ and AlCl₃ solutions. Their coagulating power should be
(a) NaCl > BaCl₂ > AlCl₃
(b) BaCl₂ > AlCl₃ > NaCl
(c) AlCl₃ > BaCl₂ > NaCl
(d) BaCl₂ > NaCl > AlCl₃

Answer : C

Question. Under the influence of an electric field, the particles in a sol migrate towards cathode. The coagulation of the same sol is studied using NaCl, Na₂SO₄ and Na₃PO₄ solutions. Their coagulating values will be in the order 
(a) NaCl > Na₂SO₄ > Na₃PO₄
(b) Na₂SO₄ > Na₃PO₄ > NaCl
(c) Na3PO₄ > Na₂SO₄ > NaCl
(d) Na₂SO₄ > NaCl > Na₃PO₄

Answer : A

Question. Gold numbers of protective colloids A, B, C and D are 0.50, 0.01, 0.10 and 0.005, respectively. The correct order of their protective powers is
(a) D < A < C < B
(b) C < B < D < A
(c) A < C < B < D
(d) B < D < A < C

Answer : C

Question. Which of the following is not emulsifying agent for W/O emulsion?
(a) Lampblack
(b) Long chain alcohol
(c) Proteins
(d) Heavy metal salts of fatty acids

Answer : C

Question. Which of the following colloid does not contain liquid as a dispersion medium?
(a) Sol
(b) Gel
(c) Emulsion
(d) Foam

Answer : B

Question. Which one of the following impurities present in colloidal solution cannot be removed by electrodialysis?
(a) Sodium chloride
(b) Potassium sulphate
(c) Urea
(d) Calcium chloride

Answer : C

Question. Brownian movement is found in
(a) Colloidal solution
(b) Suspension
(c) Saturated solution
(d) Unsaturated solution

Answer : A

Question. Which of the following phenomenon occurs when the precipitate of Mg(OH)2 attains blue colour in presence of magneson reagent?
(i) Absorption of solvent
(ii) Adsorption of coloured substance
(iii) Absorption and adsorption both of solvent
(iv) Adsorption of solvent
(a) (i) and (ii)
(b) (ii) only
(c) (ii) and (iv)
(d) (iii) only

Answer : C

Question. Fog is a colloidal solution of
(a) solid in gas
(b) gas in gas
(c) liquid in gas
(d) gas in liquid.

Answer : C

Question. Which property of colloidal solution is independent of charge on the colloidal particles?
(a) Electroosmosis
(b) Tyndall effect
(c) Coagulation
(d) Electrophoresis

Answer : B

Question. The protecting power of lyophilic colloidal sol is expressed in terms of
(a) coagulation value
(b) gold number
(c) critical micelle concentration
(d) oxidation number.

Answer : B

Question. Which one of the following forms micelles in aqueous solution above certain concentration?
(a) Dodecyl trimethyl ammonium chloride
(b) Glucose
(c) Urea
(d) Pyridinium chloride

Answer : A

Question. Position of non-polar and polar part in micelle
(a) polar at outer surface but non-polar at inner surface
(b) polar at inner surface non-polar at outer surface
(c) distributed over all the surface
(d) are present in the surface only.

Answer : A

Question. Emulsions can be broken into constituent liquid by ______.
(a) heating
(b) freezing
(c) centrifuging
(d) all of the options

Answer : D

Question. In which of the following Tyndall effect is not observed ?
(a) Suspensions
(b) Emulsions
(c) Sugar solution
(d) Gold sol

Answer : C

Question. Which of the following is not the condition for Tyndall effect?
(a) The refractive indices of dispersed phase and dispersion medium should differ greatly in magnitude.
(b) The diameter of the dispersed particles is not much smaller than the wavelength of light used.
(c) Tyndall effect is observed only when viewed from the direction of the passage of light.
(d) all of the options are required conditions for Tyndall effect.

Answer : C

Question. Which of the following is not true about the emulsion?
(a) Emulsion can be broken into constituent liquids by heat, freezing
(b) Emulsion of oil in water is generally unstable
(c) Emulsion do not show the Tyndall effect
(d) They show brownian motion

Answer : C

Question. Which of the following method is used for coagulation of the sol?
(a) By mixing two oppositely charged sols.
(b) By electrophoresis.
(c) By addition of electrolytes.
(d) All of the options.

Answer : D

Question. The ability of anion, to bring about coagulation of a given colloid, depends upon
(a) magnitude of the charge
(b) both magnitude and charge
(c) its charge only
(d) sign of the charge alone.

Answer : B

Question. The disease kala azar is caused by
(a) colloidal antimony
(b) milk of magnesia
(c) argyrols
(d) colloidal gold

Answer : A

Question. Which one of the following impurities present in colloidal solution cannot be removed by electrodialysis?
(a) Sodium chloride
(b) Potassium sulphate
(c) Urea
(d) Calcium chlorid

Answer : C

Question. Which of the following statements is incorrect regarding physisorption?
(a) It occurs because of van der Waals’ forces
(b) More easily liquefiable gases are adsorbed readily
(c) Under high pressure, it results into multimolecular layer on adsorbent surface
(d) Enthalpy of adsorption (ΔHadsorption) is slow and positive

Answer : D

Question. The volume of the gases H₂, CH₄, CO₂ and NH₃ adsorbed by one of activated charcoal at 298 K are in order
(a) H₂ > CO₂ > CH₄ > NH₃
(b) H₂ > CH₄ > CO₂ > NH₃
(c) NH₃ > CO₂ > CH₄ > H₂
(d) NH₃ > CH₄ > CO₂ > H₂

Answer : C

Question. Which one of the following method is commonly used method for destruction of colloid?
(a) Dialysis
(b) Condensation
(c) Filteration by animal membrane
(d) By adding electrolyte

Answer : D

Question. The coagulation values in millimoles per litre of the electrolytes used for the coagulation of As₂S₃ are given below :
I. (NaCl) = 52, II. (BaCl₂) = 0.69,
III. (MgSO₄) = 0.22
The correct order of their coagulating power is
(a) I > II > III
(b) II > I > III
(c) III > II > I
(d) III > I > II

Answer : C

Question. At the critical micelle concentration (CMC) the surfactant molecules
(a) associate
(b) dissociate
(c) decompose
(d) become completely soluble.

Answer : A