Question

What are amphoteric oxides?

Hint:

Remember 'Al' and 'Zn' as the "dual-nature" metals whose oxides (\( Al_2O_3 \) and \( ZnO \)) are the most common examples of amphoteric oxides in exams.

Answer 1

Step 1: Understanding the Concept:
Metal oxides are generally basic in nature, while non-metal oxides are generally acidic. However, some metal oxides exhibit a dual nature, meaning they can behave as both acids and bases depending on the reactant.
Step 2: Detailed Explanation:
Oxides that show both acidic and basic behavior are called amphoteric oxides.
They react with acids to form salt and water (acting as a base) and also react with strong bases to form salt and water (acting as an acid).
Examples include Aluminium oxide (\( Al_2O_3 \)) and Zinc oxide (\( ZnO \)).
Reaction with acid: \( ZnO + 2HCl \rightarrow ZnCl_2 + H_2O \)
Reaction with base: \( ZnO + 2NaOH \rightarrow Na_2ZnO_2 + H_2O \)
Step 3: Final Answer:
Amphoteric oxides are metal oxides which react with both acids as well as bases to produce salts and water.