HO acts as a reducing agent in:
- A
- B
- C
- D
HO acts as a reducing agent in:
Correct answer:D
Standard Method
Given: We must identify the reaction in which acts as a reducing agent.
Find: The correct option where is oxidized while reducing the other species.
A reducing agent itself undergoes oxidation. In , the oxidation state of oxygen is .
From the provided solution, the correct option is stated as D, and the reaction shown is In this reaction, oxygen in changes from to in , so is oxidized.
Also, is reduced to . Therefore, acts as the reducing agent in this reaction.
There is a discrepancy in the source: the worked reaction corresponds to option A in the listed options, but the solution labels it as D. Since the solution is the primary source and explicitly states D, the answer is recorded as D.

Oxidation Number Check
Given: Oxygen in has oxidation number .
Find: In which reaction this oxygen is oxidized.
Check the reaction identified in the solution: Here, oxygen from appears as , where the oxidation number is Thus, This is oxidation of . Hence behaves as a reducing agent.
Therefore, the reaction displayed in the solution is the required one, and the source solution marks the correct option as D.
Assuming is always an oxidizing agent is incorrect because it can act as both oxidizing and reducing agent. Always check whether oxygen goes from to a higher or lower oxidation state.
Comparing only the other reactant and ignoring the change in is wrong. To identify the reducing agent, verify that itself gets oxidized.
Trusting the option label without matching it to the reaction can cause errors. Here the solution text marks D, but the displayed reaction matches listed option A; compare both the label and the chemical equation.
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