Question

Which of the following is an amphoteric oxide?

• A. Na$_2$O
• B. K$_2$O
• C. CO$_2$
• D. Al$_2$O$_3$

Hint:

Amphoteric oxides react with both acids and bases (e.g., Al$_2$O$_3$, ZnO).

Answer 1

The Correct Option is D

Amphoteric oxides are compounds that can react both as acids and bases. This unique property allows them to neutralize both acidic and basic substances, making them versatile in chemical reactions.

To determine which of the given oxides is amphoteric, let's analyze each one:

1. Na₂O (Sodium Oxide): This is a basic oxide. It reacts with acids to form salts and water, indicating its basic nature.
2. K₂O (Potassium Oxide): Similar to sodium oxide, this is also a basic oxide. It reacts with acids to produce salts and water.
3. CO₂ (Carbon Dioxide): This is an acidic oxide. It reacts with bases forming carbonates and bicarbonates.
4. Al₂O₃ (Aluminum Oxide): This is an amphoteric oxide. It can react with both acids and bases:
   • Reaction with an acid (e.g., HCl):
   • \(Al_2O_3 + 6HCl \rightarrow 2AlCl_3 + 3H_2O\)
   • Reaction with a base (e.g., NaOH):
   • \(Al_2O_3 + 2NaOH + 3H_2O \rightarrow 2NaAl(OH)_4\)

Based on these properties, Al₂O₃ is the correct answer as it exhibits amphoteric behavior, reacting both with acids and bases.