Which one of the following methods can be used to separate anthracene from a mixture of salt and anthracene?

The correct answer is B, Sublimation. Anthracene sublimes on heating, while common salt does not, so heating the mixture separates them. Sublimation is the change of a solid directly into vapour without passing through the liquid state. To separate the mixture, it is placed in a china dish covered by an inverted funnel with a cotton plug and heated gently. The anthracene turns into vapour, which cools on the cold walls of the funnel and deposits as solid anthracene, while the salt, which does not sublime, stays in the dish. Other substances separated in the same way include camphor, naphthalene, ammonium chloride and iodine. Option A is wrong because distillation separates liquids, or a liquid from a dissolved solid, by their boiling points. Option C is wrong because evaporation recovers a dissolved solid from a solution and would not separate two solids. Option D is wrong because chromatography separates small amounts of dissolved components, such as the dyes in ink, and is not needed here. Exam tip: camphor, naphthalene, anthracene, ammonium chloride and iodine are separated by sublimation.