Amphoteric oxides are the oxides that behave as both acidic and basic oxides. Amphoteric oxides have properties of acidic as well as basic oxides that neutralize both acids and bases. The non-metallic oxides are generally acidic and the metallic oxides are basic. Metallic oxides are known as amphoteric oxides which display both the basic and acidic nature. Elements that form amphoteric oxides have some metals and some of the non-metals characteristics. Amphoterism is based upon an oxide’s oxidation state. Amphoteric oxides are classified as metal oxides that react with both acids as well as bases to create salts and water.
Amphoteric oxides react with both acids and alkalis to form salt and water. Examples of amphoteric oxides are zinc oxide and aluminium oxide.
ZnO(s) + 2HCl(aq) → ZnCl2(aq) + H2O(l)
ZnO(s) + 2NaOH(a) → Na2ZnO2(aq) + H2O(l)
Al2O3(s) + 6HCl(aq) → 2AlCl3(aq) + 3H2O(l)
Al2O3(s) + 2NaOH(aq) → 2NaAlO2(aq) + H2O(l)