Question

What do you understand by amphoteric oxides? Explain with the help of an example.

Answer 1

Metal oxides that can act as an acid as well as base in a reaction to produce a salt and water are called amphoteric metal oxides. For example, oxides of aluminium and zinc are amphoteric in nature.

• Aluminium oxide on reaction with hydrochloric acid form aluminium chloride salt and water and thus, acts as a base in the reaction.

Aluminium oxide + Hydrochloric acid $\to$ Aluminium chloride + Water

• Aluminium oxide on reaction with sodium hydroxide form sodium aluminate salt and water and thus, acts as an acid.

Aluminium oxide + Sodium hydroxide $\to$ Sodium aluminate + Water