MP Board · Class 10 · Science · Metals and Non-metalsWhat are amphoteric oxides? Give two examples of amphoteric oxides and write balanced chemical equations to show the reaction of aluminium oxide with both an acid and a base.
Amphoteric oxides are metal oxides that exhibit both acidic as well as basic behavior. This means they react with both acids and bases to produce salt and water as products. While most metal oxides are basic in nature, oxides of certain metals like aluminium and zinc display this dual characteristic.
Two common examples of amphoteric oxides are:
- Aluminium oxide ($ \text{Al}_2\text{O}_3 $)
- Zinc oxide ($ \text{ZnO} $)
Chemical Reactions of Aluminium Oxide ($ \text{Al}_2\text{O}_3 $):
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Reaction with an Acid (Hydrochloric acid): $$\text{Al}_2\text{O}_3(s) + 6\text{HCl}(aq) \rightarrow 2\text{AlCl}_3(aq) + 3\text{H}_2\text{O}(l)$$ In this reaction, aluminium oxide acts as a basic oxide and reacts with hydrochloric acid to form aluminium chloride and water.
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Reaction with a Base (Sodium hydroxide): $$\text{Al}_2\text{O}_3(s) + 2\text{NaOH}(aq) \rightarrow 2\text{NaAlO}_2(aq) + \text{H}_2\text{O}(l)$$ In this reaction, aluminium oxide acts as an acidic oxide and reacts with sodium hydroxide to form sodium aluminate and water.
Thus, amphoteric oxides demonstrate a unique chemical property by neutralizing both acids and bases.