Q1. [1]
Metal oxides generally react with acids, but few oxides of metal also react with bases. Such metallic oxides are :
I. MgO
II. ZnO
III. Al₂O₃
IV. CaO
- (a) I and II
- (b) II and III
- (c) III and IV
- (d) I and IV
Previously asked in CBSE board exam
2023 31/6/1 Q1
Generated by claude-sonnet-4-6 · 2026-06-15 06:50 · grounding rag
Model Answer
(b) II and III
ZnO and Al₂O₃ are amphoteric oxides — they react with both acids and bases. MgO and CaO are purely basic oxides that react only with acids.
Explanation
The key term here is amphoteric oxide — an oxide that reacts with both acids and bases. The textbook explicitly names only zinc oxide (ZnO) and aluminium oxide (Al₂O₃) as examples. MgO and CaO are basic oxides (their metals are high in the activity series and form strongly basic compounds). Examiners expect you to recall these two specific examples from the chapter.
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