Question

How will you demonstrate the process of sublimation with the help of a suitable example ?

Answer 1

Sublimation is the process in which a solid directly changes to vapours on heating and vapours get converted to solids on cooling. Substances that undergo sublimation are ammonium chloride, naphthalene, camphor, benzoic acid, etc.

$\mathrm{SOLID}\underset{\mathrm{Cooling}}{\overset{\mathrm{Heating}}{\rightleftharpoons }}\mathrm{VAPOUR}$

Examples:

1. Naphthalene balls are kept in woolen and silk clothes to protect the clothes from insects and moths. After some time naphthalene balls disappear leaving no residue behind as they undergo sublimation and the vapours formed from them protect the clothes from insects.
2. Solid carbon dioxide also called dry ice show the property of sublimation and hence gets sublimed. It is always dry and no liquid is formed on its surface. It is used to keep medicines, and ice creams at their freezing point.