Pumice stone is an example of -

Question

Accepted Answer

B. 1. Colloids are classified based on the physical state of the **dispersed phase** and the **dispersion medium**.

2. When both the dispersed phase and the dispersion medium are solids, the colloid is called a **solid sol**.
$$	ext{Solid sol} = 	ext{solid dispersed in solid}$$

3. Pumice stone is a porous volcanic rock in which tiny pockets of trapped gas are locked inside a solid rock matrix, so it fits the pattern of one solid phase dispersed within another solid.

4. This is different from a **gel** (liquid dispersed in solid, like jelly), a **foam** (gas dispersed in liquid, like whipped cream), and a **sol** (solid dispersed in liquid, like paint).

Hence, the answer is **B. solid sol**.