CBSE Class 9 Answered

By the process of sublimation. Naphthalene undergoes sublimation whereas sodium chloride does not.

Procedure:

1. Take the mixture of sodium chloride and naphthalene and put it in a china dish.

2. Put an inverted funnel over the china dish.

3. Put a cotton plug on the stem of the funnel.

4. Now, heat slowly and observe.

5. Since naphthalene undergoes sublimation, it gets deposited on the walls of teh china dish whereas sodium chloride remains in the china dish.

A change of state directly from solid to gas without changing into liquid state (or vice versa) is called sublimation.