UPSC CDS 2 2020 GK Paper

Ammonium chloride is isolated from a mixture of sodium chloride and ammonium chloride by the process of sublimation. Ammonium chloride can be sublimed whereas sodium chloride cannot be sublimed. When a mixture of sodium chloride and ammonium chloride is heated, ammonium chloride changes its state from solid to vapor. The vapors of ammonium chloride are condensed on the cold surface. Sodium chloride is left behind.