(d) Assertion (A) is false, but Reason (R) is true.
Sodium oxide (Na₂O) is a basic oxide, not amphoteric. Amphoteric oxides (e.g., Al₂O₃, ZnO) react with both acids and bases — the definition in Reason (R) is correct.
Source: What you have learnt, Chapter 3
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The key distinction: Na is an active metal, so Na₂O is purely basic. Only oxides like Al₂O₃ and ZnO (mentioned explicitly in the textbook) are amphoteric. The definition of amphoteric oxide given in Reason (R) is accurate, making (d) the correct option. Examiners expect students to recall specific examples of amphoteric oxides from Chapter 3.