NEET Chemistry: Chemistry - Surface Chemistry questions with solutions

Q1. At high concentration of soap in water, soap behave as:

1. molecular solid
2. associated colloid
3. macromolecular colloid
4. Iyophilic colloid

Answer: associated colloid

At high concentration, soap molecules do not remain as isolated particles; they aggregate into micelles. Such systems are called associated colloids because the colloidal particles are formed by association of many small molecules.

Q2. A colloidal system having a solid substance as a dispersed phase and a liquid as a dispersion medium are classified as:

1. solid sol
2. gel
3. emulsion
4. sol

Answer: sol

A sol is a colloidal system in which solid particles are dispersed throughout a liquid dispersion medium. Since the dispersed phase is solid and the medium is liquid, the correct classification is sol.

Q3. Which of the following is not a colloidal solution?

1. Solid-Solid
2. Liquid-Liquid
3. Gas-Gas
4. Solid-Liquid

Answer: Gas-Gas

A colloidal solution requires a dispersed phase and a dispersion medium, so the two components must be in different states or at least form a dispersed system. Gas-gas mixtures are always true solutions because gases mix completely at the molecular level, so they do not form colloids.