Question

Which of the following reactions is not a disproportionation reaction?

• A. \( \text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2 \)
• B. \( \text{P}_4 + 3 \text{NaOH} + 3 \text{H}_2O \rightarrow 3 \text{NaH}_2\text{PO}_2 + \text{PH}_3 \)
• C. \( 2\text{H}_2\text{O}_2 \rightarrow 2\text{H}_2\text{O} + \text{O}_2 \)
• D. \( 2\text{Cu}^+ \rightarrow \text{Cu}^{2+} + \text{Cu} \)

Hint:

In disproportionation, one element is oxidized and reduced in the same reaction. Simple decomposition is not disproportionation.

Answer 1

The Correct Option is A

A disproportionation reaction involves simultaneous oxidation and reduction of the same element.
- (1) is not disproportionation. It's a decomposition reaction, with no redox occurring for the same element.
- (2), (3), and (4) involve an element undergoing both oxidation and reduction → disproportionation reactions.