Which of the following metal oxides is amphoteric (reacts with both acids and bases)?
A{'text': 'Aluminium oxide (Al₂O₃)', 'label': 'A'}
B{'text': 'Sodium oxide (Na₂O)', 'label': 'B'}
C{'text': 'Magnesium oxide (MgO)', 'label': 'C'}
D{'text': 'Copper oxide (CuO)', 'label': 'D'}
Answer & Solution
Correct answer: A. {'text': 'Aluminium oxide (Al₂O₃)', 'label': 'A'}
1. Most metal oxides are basic (Na₂O, MgO, CuO react only with acids).
2. NCERT names Al₂O₃ and ZnO as amphoteric — they react with BOTH acids and bases.
3. Al₂O₃ + 6 HCl → 2 AlCl₃ + 3 H₂O (acidic behaviour).
4. Al₂O₃ + 2 NaOH → 2 NaAlO₂ + H₂O (basic behaviour).
_Source: NCERT Class 10 Science, Ch 3 "Metals and Non-metals", §3.2_
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