The correct option is (b).
Explanation
Boiling is a physical phase transition where a liquid turns into a gas (vapour). It is fundamentally different from evaporation in terms of the site of the phenomenon and the temperature at which it occurs.- Statement 1 is Incorrect: Boiling is a bulk phenomenon. This means that the entire mass of the liquid is involved in the process. Bubbles of vapour form within the bulk of the liquid and rise to the surface. In contrast, evaporation is a surface phenomenon.
- Statement 2 is Correct: The boiling point is defined as the specific temperature at which the vapour pressure of the liquid becomes equal to the external atmospheric pressure. At this temperature, the liquid begins to boil.
- Statement 3 is Incorrect: Since boiling is a bulk phenomenon, particles from the entire bulk of the liquid gain the necessary energy to overcome intermolecular forces and change into the vapour state. It is in evaporation that particles only from the surface gain energy to escape.
Key Takeaway: Boiling is a bulk phenomenon that occurs at a fixed temperature (boiling point), whereas evaporation is a surface phenomenon that can occur at any temperature below the boiling point.