Question

The number of amphoteric, basic, and acidic oxides among the following respectively are: \[ \text{CrO}_3, \, \text{MgO}, \, \text{K}_2\text{O}, \, \text{B}_2\text{O}_3, \, \text{Al}_2\text{O}_3, \, \text{In}_2\text{O}_3, \, \text{PbO}, \, \text{As}_2\text{O}_3 \]

• A. 3, 2, 3
• B. 3, 3, 2
• C. 3, 4, 1
• D. 2, 5, 3

Hint:

Amphoteric oxides show both acidic and basic characteristics, while basic oxides react with acids and acidic oxides react with bases.

Answer 1

The Correct Option is B

Step 1:
Classify the oxides as acidic, basic, or amphoteric: - Basic oxides: \( \text{MgO}, \, \text{K}_2\text{O} \)
- Acidic oxides: \( \text{B}_2\text{O}_3, \, \text{As}_2\text{O}_3 \)
- Amphoteric oxides: \( \text{CrO}_3, \, \text{Al}_2\text{O}_3, \, \text{In}_2\text{O}_3, \, \text{PbO} \)

Step 2:
Count the oxides in each category:
- Amphoteric: 3 (\( \text{CrO}_3, \, \text{Al}_2\text{O}_3, \, \text{In}_2\text{O}_3 \))
- Basic: 3 (\( \text{MgO}, \, \text{K}_2\text{O} \))
- Acidic: 2 (\( \text{B}_2\text{O}_3, \, \text{As}_2\text{O}_3 \)) Thus, the correct answer is option (2).