Question

1. How to separate ammonium chloride + sodium chloride. Explain.

Answer 1

• There are many ways in separating mixtures of chlorides salts such as that of sodium chloride and ammonium chloride.
• It can be done by crystallization, filtration or sublimation.
• The easiest method among the three is separation by sublimation.
• ​ Ammonium chloride sublimes upon heating. Actually, the sublimation(phase transition from direct solid to gas on heating) is a decomposition of ammonium chloride forming ammonia and hydrogen chloride.
• The reaction can be written as:
• $N{H}_{4}Cl\left(s\right)⟶N{H}_3\left(g\right)+HCl\left(g\right)$
• Sodium chloride on the other hand doesn't sublime and has a higher melting point than ammonium chloride.
• If we want to separate the mixture, we have to heat up to 330-350 degrees Celsius and collect the gas that will be produced.