Question

Which of the following equations denotes that H$_2$O$_2$ acts as a reducing agent?

• A. PbS + 4H$_2$O$_2$ $\rightarrow$ PbSO$_4$ + 4H$_2$O
• B. NaNO$_2$ + H$_2$O$_2$ $\rightarrow$ NaNO$_3$ + H$_2$O
• C. Ag$_2$O + H$_2$O$_2$ $\rightarrow$ 2Ag + O$_2$ + H$_2$O
• D. 2KI + H$_2$O$_2$ + H$_2$SO$_4$ $\rightarrow$ I$_2$ + K$_2$SO$_4$ + H$_2$O

Hint:

H$_2$O$_2$ is a versatile compound—it can act as both an oxidising agent and a reducing agent depending on the reaction.

Answer 1

The Correct Option is C

Step 1: Recall that a reducing agent is a substance that gets oxidised while reducing another substance.
Step 2: Examine option (C). In this reaction, silver oxide (Ag$_2$O) is reduced to metallic silver (Ag).
Step 3: Hydrogen peroxide (H$_2$O$_2$) is oxidised to oxygen (O$_2$).
Step 4: Since H$_2$O$_2$ undergoes oxidation and causes reduction of Ag$_2$O, it acts as a reducing agent in this reaction.
Step 5: In the other options, H$_2$O$_2$ acts as an oxidising agent.