Answer :
1. Answer : (c) heterogeneous nature of sols
Explanation: Tyndall effect confirms the heterogeneous nature of the colloidal solution.it is observed due to the scattering of dust particles. Tyndall effect is used to distinguish between the true solution and the colloidal solution.
2. Answer : (b) Gum
Explanation: In such solids, the dispersed phase does not easily precipitate and the sols are quite stable. These sols are reversible in nature.If water is used as the dispersion medium, lyophilic sols are called hydrophilic sols. Starch, gum, gelatin, egg albumin etc.
3. Answer : (a) zeolite
Explanation: The shape-selective catalysis is a reaction catalysed by Zeolites. Because the structure of Zeolites is like a honeycomb. Hence it is used as the catalyst in the chemical reaction. Zeolites are especially used as Shape-selective catalysis.
4. Answer : (b) Transition metals
Explanation: The transition metals are considered to make the most efficient catalysts. This is because, when these metals are with suitable reactants, they form unstable intermediate products that can lower the activation energy and thereby making the reaction faster.
5. Answer : (a) NO
Explanation: The process of producing sulfuric acid by oxidizing sulfur dioxide with moist air, using gaseous nitrogen oxides as catalysts, is known as Lead chamber process. This reaction takes place primarily in a series of large, boxlike chambers of sheet lead.
6. Answer : (c) at high temperature
Explanation: Enzymes are effective only at optimum temperature. They become ineffective at very high temperature.
7. Answer : (b) Colloidal solution of palladium
Explanation: An excellent absorbed hydrogen gas is palladium. Therefore, colloidal solutions of palladium could adsorb greater volume of hydrogen gas as the surface area of palladium is the most colloidal solution of palladium.
8. Answer : (d) SO2
Explanation: The amount of gas adsorbed by a solid depends on the nature of gas. In general, easily liquefiable gases. Easily liquefiable gases will have higher critical temperatures are readily adsorbed as van der Waals’ forces are stronger near the critical temperatures.SO2 is having the maximum critical temperature and hence it gets adsorbed most easily on the charcoal gas mask.
9. Answer : (b) Heterogeneous catalysis
Explanation: Adsorption theory of Heterogeneous catalyst is adsorption theory of catalysis, the reactions in their gaseous state on in their dissolved state in any solution gets adsorbed on the surface of
a suitable catalyst in its solid state.
10. Answer : (a) gel
Explanation: A colloidal system in which liquid is a dispersed phase and solid is dispersion medium is known as Gel. Example-Cheese, jellies.
11. Answer : (d) associated colloids
Explanation: Associated colloids are substances which at low concentrations behave as normal strong electrolytes, but at higher concentrations exhibit colloidal behaviour due to the formation of aggregates.
The aggregated particles formed are called micelles. The formation of micelles takes place only above a particular temperature called Kraft temperature and above a particular concentration called critical micelle concentration.
12. Answer : (b) Kraft temperature
Explanation: The formation of micelles takes place only above a particular temperature called Kraft temperature (TK).
13. Answer : (b) To coagulate the suspended impurities
Explanation: When alum is added to raw water it reacts with the bicarbonates alkalinities present in water and forms a gelatinous precipitate. It neutralizes all the suspended impurities of water resulting in their coagulation.
14. Answer : (c) electroosmosis
Explanation: When movement of particles (electrophoresis) is prevented by some suitable means, it is observed that the dispersion medium begins to move in an electric field. This phenomenon is termed as electroosmosis.
15. Answer : (d) Van der waal's forces
Explanation: When the force of attraction existing between adsorbate and adsorbent are weak Vanderwaal forces of attraction, the process is called Physical Adsorption or Physisorption. When the force of attraction existing between adsorbate and adsorbent are chemical forces of attraction or chemical bond, the process is called Chemical Adsorption.
16. Answer : (d) Electrophoresis
Explanation: Colloidal particles possess some type of electric charge. The migration of colloidal particles under the influence of an electric field is known as electrophoresis.
17. Answer : (c) Gold
Explanation: Gold is dissolved in the aqua medium and it further reduces to give a purple precipitate. Therefore, purple of cassius is a colloidal sol of gold.
18. Answer : (a) Liquid is dispersed in liquid
Explanation: Milk is an emulsified colloid of Liquid is dispersed in liquid where liquid butterfat globules dispersed within a water-based solution.
19. Answer : (c) Gold solution
Explanation: Gold sol is a lyophobic sol. Gold particles have very less affinity towards dispersion medium, hence its sol can be easily coagulated.
20. Answer : (c) water is dispersed in fat
Explanation: A colloid is a mixture where a particular substance is trapped in a given dispersion medium but do not get mixed chemically. Butter is a colloidal formed when water is dispersed in fat.
21. Answer : (a) which retards the rate of reaction
Explanation: The catalyst which decreases the rate of reaction is known as inhibitor or negative catalyst and the process is known as negative catalysis or inhibition. Negative catalysts are useful to slow down or stop any unwanted reactions.
22. Answer : (c) Aluminium which coagulates the mud particles
Explanation: Alum is added to water in order to destabilize the mud particles suspended in it. This process is known as coagulation. Alum helps in purifying water by aluminium which helps to coagulate the mud particles.
23. Answer : (b) Formaldehyde solution
Explanation: Formaldehyde solution is an emulsifier which is added in the milk as it acts as a preserving agent for the milk.
24. Answer : (c) liquid in a gas
Explanation: Fog or cloud is a colloidal dispersion of water droplets in a dispersion medium of gas. When the dispersion medium is gas, the dispersed phase can be solid or liquid but not gas.
25. Answer : (a) Protective power of lyophilic colloid
Explanation: The Gold Number is the minimum weight (in milligrams) of a protective colloid required to prevent the coagulation of 10 ml of a standard hydro gold sol when 1 ml of a 10% sodium chloride solution is added to it.
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