Question

The reaction $2H_2{O}_2\to 2H_{2}O+O_2$ is:

• A. a redox reaction
• B. a hydrolysis reaction
• C. a solvolysis reaction
• D. an oscillatory reaction
• E. disproportionation

Answer 1

Answer: (E)

$\underset{+1-1}{H_2{O}_2}+\underset{+1-1}{H_2{O}_2}\to 2\underset{+1-2}{H_{2}O}+\underset{0}{O_2}$ Here the oxidation number of hydrogen is not changed while the oxidation number of oxygen in $H_2{O}_2,H_{2}O$ and $O_2$ is $-1,-2$ and 0. Hence, oxygen in undergoing oxidation to $O_2$ ( $-1$ to 0) as well as reduction to $H_{2}O(-1to-2)$ . Such reactions where a molecule acts as both oxidising and reducing agent are called disproportionation.