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The most suitable method for separating a mixture of naphthalene and benzoic acid is

1. Chromatography
2. Crystallisation
3. Distillation
4. Sublimation

Correct answer: Sublimation

Solution

Naphthalene is a volatile solid that sublimes readily (sublimation point ~80 deg C). Benzoic acid also sublimes but requires higher temperature. In practice, gentle heating of the mixture causes naphthalene to sublime first and collect on a cold surface, separating it from benzoic acid. Sublimation is the standard method taught for separating such mixtures in NCERT chemistry.

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