Question

A student purchases common salt from the market which contains ammonium chloride (${NH}_{4}Cl$ ) in it. Identify the technique that he should adopt to obtain pure $NaCl$.

• A. Mix the sample in water and evaporate the solution.
• B. Mix the sample in water and evaporate the decanted solution.
• C. Mix the sample in acetone and evaporate the decanted solution.
• D. Heat the sample, then mix it in water and evaporate the decanted solution.

Answer 1

The correct option is C

Mix the sample in acetone and evaporate the decanted solution.

Ammonium chloride is a volatile solid and sublimes on heating.

The transition of the substance directly from solid to gas phase, without passing through the intermediate liquid phase is called sublimation.

The white fumes of $N{H}_{4}Cl$ can be trapped by putting an inverted funnel having a cotton plug. The vapours are trapped in the separating funnel. NaCl does not sublime, both components are separated.