During the adsorption of a gas on the surface of a solid, which o

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 Multiple Choice QuestionsMultiple Choice Questions

101.

The stability of a lyophobic colloid is due to

  • adsorption of covalent molecules on the colloid

  • the size of the particles

  • the charge on the particles

  • Tyndall effect


102.

Which of the following cations will have minimum flocculation value for arsenic sulphide sol?

  • Na+

  • Mg2+

  • Ca2+

  • Al3+


103.

Adsorption theory is applicable for

  • homogeneous catalysis

  • heterogeneous catalysis

  • autocataylsis

  • induced catalysis


104.

All colloidal dispersions have

  • low osmotic pressure

  • no osmotic pressure

  • high osmotic pressure

  • very high osmotic pressure


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105.

Silver iodide is used for producing artificial rain because AgI

  • is easy to synthesize

  • has crystal structure similar to ice

  • is insoluble in water

  • is easy to spray at high altitude


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106.

During the adsorption of a gas on the surface of a solid, which of the following is true?

  • G > 0, H < 0, S < 0

  • G < 0, H < 0, S < 0

  • G <0, H < 0, S > 0

  • G <0, H > 0, S < 0


B.

G < 0, H < 0, S < 0

During the adsorption of a gas on the surface of a solid there is decrease in surface energy, i.e., it is an exothermic process. Therefore, H < 0. Again when a gas is adsorbed, the freedom of movement of its molecules becomes restricted. This leads to decrease in the entropy of the gas after adsorption. Therefore, S < 0.

From equation, G = H - TS, G can be negative if process is spontaneous. Since, adsorption process is a spontaneous process, therefore, G < 0.


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107.

A crystalline solid X reacts with dil. HCl to liberate a gas Y. Y decolourises acidified KMnO4. When a gas 'Z' is slowly passed into an aqueous solution of Y, colloidal sulphur is obtained X and Z could be respectively

  • Na2S, SO3

  • Na2SO4, H2S

  • Na2SO3, H2S

  • Na2SO4, SO2


108.

Gold sol is not

  • a macromolecular colloid

  • a lyophobic colloid

  • a multimolecular colloid

  • negatively charged colloid


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109.

For Freundlich isotherm a graph of log x/m is plotted against log p. The slope of the line and its y-axis intercept, respectively corresponds to

  • 1n , k

  • log 1n , k

  • 1n , log k

  • log 1n, log k


110.

The electrolyte having maximum flocculation value for AgI/Ag+ sol is

  • NaCl

  • Na2S

  • Na2SO4

  • Na3PO4


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