Multiple Choice Questions

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Which of the following is true for spontaneous adsorption of H2 gas without dissociation on solid surface.

  • Process is exothermic and ΔS <0.

  • Process is exothermic and ΔS >0

  • Process is endothermic and ΔS <0.

  • Process is endothermic and ΔS >0.


A.

Process is exothermic and ΔS <0.

Adsorption of H2 gas on solid surface is exothermic and entropy decreases in the process.

therefore, ΔS<0.


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Which are of the following is a false statement?

  • Cell fluid is an example of sol

  • Butter is an example of gel

  • Hair cream is an example of emulsion

  • Cheese is an example of foam


Which of the following statements is correct for Tyndall effect?

  • Scattering and polarising of light by small suspended particles is called Tyndall effect

  • Tyndall effect of colloidial particles is due to dispersion of light

  • Tyndall effect is due to refraction of light

  • Tyndall effect is zig-zag motion of suspended particles.


Milk is an emulsion in which

  • a gas is dispersed in water

  • lactose is dispersed in water

  • milk fat is dispersed in water

  • a solid is dispersed in water


Micelles are

  • adsorbed catalyst

  • ideal solution

  • gel

  • associated colloids


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A colloidal system having a solid substance as a dispersed phase and a liquid as a dispersion medium is classified as

  • solid sol

  • gel

  • emulsion

  • sol


Which one of the following is used in the hardening of leather?

  • Light sensitive silver bromide in gelatin

  • Sodium lauryl sulphate

  • Alum

  • Tannin


Which one of the following is an emulsion?

  • Milk

  • Soap lather

  • Butter

  • Vanishing cream


At Critical Micell Concentration (CMC), the surfactant molecules

  • dissociate

  • associate

  • become completely soluble

  • decompose


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Which of the following is a lyophobic colloid?

  • sulphur

  • starch

  • gum arabica

  • gelatin


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