Question

Which separation technique will you apply for the separation of the following?

Camphor from the mixture of camphor and sodium chloride

Answer 1

A mixture of Camphor and Sodium chloride $\left(\mathrm{NaCl}\right)$ can be separated by using sublimation.

Sublimation: The process of conversion of a substance from the solid state into the gaseous state on heating directly without converting into the liquid state.

• Example: Camphor, Iodine $\left({\mathrm{I}}_2\right)$, Naphthalene, Anthracene
• $\mathrm{Camphor}\left(\mathrm{s}\right)\underset{\mathrm{Cool}}{\overset{\mathrm{Heat}}{\rightleftarrows }}\mathrm{Camphor}\left(\mathrm{g}\right)$

When heated, camphor can undergo sublimation whereas sodium chloride does not undergo sublimation. As a result, camphor leaves the mixture when heated and sodium chloride is left behind.

Process of separation of camphor and sodium chloride by sublimation is as follows:

• Take the mixture into a china dish.
• Cover the mixture with an inverted funnel whose stem is plugged with a cotton ball to avoid the vapours from escaping.
• Heat the china dish by placing it on a Bunsen burner over a wire gauze.
• Camphor will sublime and changes into vapours and can be seen collecting in the funnel leaving behind sodium chloride.
• The vapours in the funnel are scraped when cooled and a sublimate of camphor is obtained.
• In this way, the mixture is separated.