1. Which of the following is NOT a type of adsorption?
Answer:
Explanation:
Absorption is a bulk phenomenon where a substance uniformly enters another. It's not a type of adsorption, which is a surface phenomenon.
2. Which of the following increases with an increase in the surface area of the adsorbent?
Answer:
Explanation:
The greater the surface area, the more sites are available for adsorption, increasing the rate of adsorption.
3. What type of isotherm is represented by the equation x/m = kP^1/n?
Answer:
Explanation:
The given equation represents the Freundlich isotherm, which relates adsorption to pressure.
4. For which type of adsorption is the heat of adsorption high?
Answer:
Explanation:
Chemical adsorption involves the formation of chemical bonds, leading to higher heats of adsorption compared to physical adsorption.
5. In a colloid, the dispersed phase is:
Answer:
Explanation:
In a colloid, the dispersed phase refers to the particles, droplets, or bubbles spread throughout the dispersion medium.
6. Which method is used to purify colloids?
Answer:
Explanation:
Dialysis is a process used to remove impurities from colloidal solutions using a semi-permeable membrane.
7. The Brownian movement in colloids is caused by:
Answer:
Explanation:
The random, zig-zag motion of colloidal particles, known as Brownian movement, is due to the incessant collision with molecules of the dispersion medium.
8. Which type of colloid cannot be coagulated?
Answer:
Explanation:
All colloids can be coagulated under suitable conditions, but lyophilic colloids are more resistant to coagulation than lyophobic colloids.
9. Which phenomenon confirms the colloidal nature of a solution?
Answer:
Explanation:
Both the Tyndall effect (scattering of light by colloidal particles) and Brownian movement confirm the colloidal nature of a solution.
10. Catalysts that are in the same phase as the reactants are called:
Answer:
Explanation:
Homogeneous catalysts are in the same phase as the reactants, while heterogeneous catalysts are in a different phase.
11. Which among the following is a macromolecular colloid?
Answer:
Explanation:
Starch is a natural polymer and forms macromolecular colloids when dispersed in water.
12. The adsorption of gas on solid surface is generally:
Answer:
Explanation:
The process of adsorption is generally exothermic, as energy is released when gas molecules get adsorbed onto a solid surface.
13. Emulsions are:
Answer:
Explanation:
Emulsions are a type of colloid in which both the dispersed phase and the dispersion medium are liquids.
14. The stability of a colloidal solution is due to:
Answer:
Explanation:
The stability of colloids is mainly due to the repulsion between particles carrying the same type of charge.
15. In the adsorption of a gas on a solid, the volume of the gas adsorbed decreases with:
Answer:
Explanation:
Adsorption is usually exothermic, so increasing temperature will reduce the extent of adsorption, leading to a decrease in the volume of gas adsorbed.
16. Which of the following is NOT a property of colloids?
Answer:
Explanation:
While some colloids can conduct electricity, it's not a general property of all colloids.
17. What prevents the particles in a lyophobic sol from settling down?
Answer:
Explanation:
The stability of lyophobic sols is maintained by the charge on the particles and their Brownian motion.
18. In surface chemistry, the term "adsorbate" refers to:
Answer:
Explanation:
The adsorbate is the substance that gets adsorbed on the surface of another substance.
19. Which phenomenon is responsible for the cleaning action of soaps?
Answer:
Explanation:
Soaps clean surfaces by emulsifying grease and dirt, thereby allowing them to be washed away.
20. What type of colloids is formed when liquid is dispersed in a gas?
Answer:
Explanation:
Aerosols are colloids where a liquid or solid is dispersed in a gas.