To separate the components of a mixture of sand, common salt and ammonium chloride (or camphor) by sublimation. - Class 9th Science Lab Work

Experiment - 12

To separate the components of a mixture of sand, common salt and ammonium chloride.

Sand, common salt, and ammonium chloride form a heterogeneous mixture and can be separated easily by physical methods of separation. By selecting the right order of methods of separation, the three can be easily separated:
(i) ammonium chloride sublimes on heating;
(ii) sand is insoluble in water; and
(iii) common salt can be recovered by evaporation of its aqueous solution.

Materials Required
A china dish, a funnel, a beaker (250 mL), a cotton plug, burner, tripod stand, wire gauge, sand, common salt, ammonium chloride, water, and filter paper.

Step 1: Mixture of ammonium chloride, sand and common salt is taken in a china dish.
Step 2: Sublimation apparatus is setup as shown in Fig. 1.
Step 3: Mixture is heated. Ammonium chloride is separated on the walls of the inverted funnel.
Step 4. The residue left behind in the china dish contains sand and common salt.
Step 5. This residue mixture is dissolved in water. Common salt will be dissolved but sand will not (Fig. 2).
Step 6. The sand is filtered from the mixture using a filter paper (Fig. 3).
Step 7. Sand is separated as residue and the filterate is salt solution in water.
Step 8. Filterate (salt solution) is evaporated to evaporate the water an  to get the dry sample of common salt (Fig. 4).

Results and Discussion
Using methods of separation sequentially, ammonium chloride, sand and common salt have been separated from their mixture.

Sublimation process should be carried out carefully.
Take care while filtering so that the filter paper does not tear off.

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