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
- Crystallization
- Sublimation
- Distillation
- Chromatography
Answer
(2) Sublimation
Solution
The direct change of a solid into vapour on heating (without melting) is sublimation; sublimable compounds (e.g. camphor, naphthalene) are separated from non-sublimable impurities by this technique.
Answer: (2)