Question

Which separation method is used to separate the components of a mixture of common salt and ammonium chloride?

Answer 1

Components of a mixture of common salt i.e. Sodium chloride $\left(\mathrm{NaCl}\right)$ and Ammonium chloride $\left({\mathrm{NH}}_4\mathrm{Cl}\right)$ can be separated by sublimation.

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

• Example: Iodine, Camphor, Naphthalene, Anthracene
• $\underset{\mathrm{Ammonium}\mathrm{chloride})}{{\mathrm{NH}}_4\mathrm{Cl}\left(\mathrm{s}\right)}\underset{\mathrm{Cool}}{\overset{\mathrm{Heat}}{\rightleftarrows }}\underset{(\mathrm{Ammonium}\mathrm{chloride})}{{\mathrm{NH}}_4\mathrm{Cl}\left(\mathrm{g}\right)}$

This is because, when heated, ammonium chloride can undergo sublimation whereas common salt is non-sublimable and does not undergo sublimation.

• So, while ammonium chloride sublimes, common salt being non-volatile does not sublimes allowing the mixture to separate.