When reacting with acids, amphoteric oxides behave as bases. They accept protons (H+ ions) from the acid, forming a salt and water. For example, aluminum oxide reacts with hydrochloric acid to form aluminum chloride and water.

 When amphoteric oxides react with acids, they typically form a salt and water. For example, when zinc oxide reacts with hydrochloric acid, it produces zinc chloride and water: 

 [ ZnO+2HCl→ZnCl2+H2O ]