JEE Main 2022 · 24 June · morning · Single correct · +4 / −1
Given below are the oxides:
Na₂O, As₂O₃, N₂O, NO and Cl₂O₇
Number of amphoteric oxides is :
- (a) 0
- (b) 1
- (c) 2
- (d) 3
Answer and solution
Answer (b) 1
Solution
Chemistry ma’am · 3 steps
Sort each oxide as acidic, basic, neutral or amphoteric, and keep neutral apart from amphoteric.
- Four boxes. An acidic oxide reacts with bases, a basic oxide reacts with acids, and an amphoteric oxide reacts with both. A neutral oxide reacts with neither, so it is not amphoteric.
- Use the element. Oxides of reactive metals are basic. Oxides of non-metals in high oxidation states are acidic. Metalloids such as arsenic give amphoteric oxides.
Oxide Nature Why Na₂O basic alkali metal oxide; gives NaOH with water As₂O₃ amphoteric metalloid oxide; dissolves in both HCl and NaOH N₂O neutral reacts with neither acid nor base NO neutral reacts with neither acid nor base Cl₂O₇ acidic Cl in +7 state; it is the anhydride of HClO₄ - So. Only As₂O₃ is amphoteric, so the count is 1, option (b).
The idea to keep. Down group 15, oxides change from acidic (N, P) to amphoteric (As, Sb) to basic (Bi). Also remember N₂O, NO and CO are neutral, not amphoteric.
Answer from the NTA final answer key. Solution by PrepWiser.