Question

“On heating, some solid substances change from solid to vapour state without passing through liquid state.” The technique used for the purification of such solid substances based on the above principle is known as:

Options

• Distillation

• Chromatography

• Crystallization

• Sublimation

Answer 1

Sublimation

Explanation:

Sublimation is the process where a solid changes directly into vapour on heating, without passing through the liquid state.

This technique is used to separate a sublimable solid (like Camphor or Iodine) from non-sublimable impurities. When heated, the pure substance turns into vapour and is later collected as a pure solid on a cold surface, leaving the impurities behind.