Question

$E_{O_3|O_2}^0$ (acidic medium) $=2.07$ V
$E_{O_3|O_2}^0$ (basic medium) $=1.24$ V

$E_{H_2{O}_2|H_{2}O}^0$ (acidic medium) $=1.78$ V
$E_{O_2|H_2{O}_2}^0$ (acidic medium) $=0.695$ V
$E_{O_2|H_2{O}_2}^0$ (basic medium) $=0.076$ V
$E_{H{O}_2^{-}|O{H}^{-}}^0$ (basic medium) $=0.878$ V
Using the above data, find which of the following is incorrect?

• A. Ozone is a better oxidising agent than $H_2{O}_2$ in both acidic and basic medium.
• B. $H_2{O}_2$ is better oxidising agent in acidic medium than in basic medium.
• C. $H_2{O}_2$ is better reducing agent in basic medium than in acidic medium.
• D. In basic medium $H_2{O}_2$ reduces all $O_3$ to $O_2$ completely.

Answer 1

Answer: (D)

In basic medium $H_2{O}_2$ reduces all $O_3$ to $O_2$ completely.

In basic medium $H_2{O}_2$ oxidizes all $O_3$ to $O_2$ completely. A molecule of hydrogen peroxide loses an O atom to form water. Loss of oxygen is reduction. Thus hydrogen peroxide is reduced. A molecule of ozone gains an O atom to form 2 oxygen molecules. Gain of oxygen is oxidation. Thus, ozone is oxidized. The redox reaction is

$H_2{O}_2+O_3\to H_{2}O+2O_2$