Question

You are provided with a mixture of naphthalene and ammonium chloride by your teacher. Suggest an activity to separate them with well labelled diagram.

Answer 1

Napthalene is insoluble in water but soluble in benzene (organic solvent). Ammonium chloride is soluble in water but insoluble in benzene. Napthalene changes into vapours at room temperature whereas ammonium chloride changes into vapours on heating.

Method :

(a) Add water to the mixture and shake it vigorously to dissolve ammonium chloride.

(b) Filter the mixture. Napthalene is obtained as residue whereas, filtrate contains ammonium chloride. Crystallize the filtrate by heating till saturated solution of ammonium chloride is obtained.

(c) Cool the hot saturated solution to get crystals of ammonium chloride.