CBSE Class 9 Answered

A mixture of ammonium chloride and common salt can be separated using sublimation. The mixture is taken in a china dish and placed on a tripod stand. The china dish is covered with an inverted glass funnel. A loose cotton plug is put in the upper, open end of the funnel to prevent the ammonium chloride vapours from escaping into the atmosphere. The china dish is heated by using a burner. On heating the mixture, ammonium chloride changes into white vapours. These vapours rise up and get converted into solid ammonium chloride on coming in contact with the cold, inner walls of the funnel. Hence, pure ammonium chloride collects on the inner sides of the funnel in the form of sublimate and can be removed. Common salt remains behind in the china dish.