In which of the following reactions `H_(2)O_(2)` acts as reducing agent?
(A) `H_(2)O_(2)+2H^(+)+2e^(-) to 2H_(2)O`
(B) `H_(2)O_(2)-2e^(-) to O_(2)+2H^(+)`
(C ). `H_(2)O_(2)+2e^(-) to 2OH^(-)`
(D) `H_(2)O_(2)+2OH^(-)-2e^(-) to O_(2)+2H_(2)O`

Options

A. A,C
B. B,D
C. A,B
D. C,D

Explanation

To determine in which of the given reactions \( H_2O_2 \) acts as a reducing agent, we need to analyze each reaction and identify the oxidation states of the elements involved, particularly focusing on the oxidation state of oxygen in \( H_2O_2 \).

### Step-by-Step Solution:

1. **Understanding Reducing Agents**:
A reducing agent is a substance that donates electrons in a chemical reaction and is oxidized in the process. This means that the reducing agent itself undergoes an increase in oxidation state.

2. **Analyzing Each Reaction**:
We will analyze the oxidation states of oxygen in \( H_2O_2 \) for each reaction.

**(A)** \( H_2O_2 + 2H^+ + 2e^- \rightarrow 2H_2O \)
- In \( H_2O_2 \), oxygen is in the -1 oxidation state.
- In \( H_2O \), oxygen is in the -2 oxidation state.
- Since oxygen goes from -1 to -2, \( H_2O_2 \) is reduced, and therefore, it acts as an oxidizing agent.

**(B)** \( H_2O_2 - 2e^- \rightarrow O_2 + 2H^+ \)
- In \( H_2O_2 \), oxygen is in the -1 oxidation state.
- In \( O_2 \), oxygen is in the 0 oxidation state.
- Since oxygen goes from -1 to 0, \( H_2O_2 \) is oxidized, and therefore, it acts as a reducing agent.

**(C)** \( H_2O_2 + 2e^- \rightarrow 2OH^- \)
- In \( H_2O_2 \), oxygen is in the -1 oxidation state.
- In \( OH^- \), oxygen is in the -2 oxidation state.
- Since oxygen goes from -1 to -2, \( H_2O_2 \) is reduced, and therefore, it acts as an oxidizing agent.

**(D)** \( H_2O_2 + 2OH^- - 2e^- \rightarrow O_2 + 2H_2O \)
- In \( H_2O_2 \), oxygen is in the -1 oxidation state.
- In \( O_2 \), oxygen is in the 0 oxidation state.
- Since oxygen goes from -1 to 0, \( H_2O_2 \) is oxidized, and therefore, it acts as a reducing agent.

3. **Conclusion**:
From the analysis, \( H_2O_2 \) acts as a reducing agent in reactions (B) and (D).

### Final Answer:
**(B) and (D)** are the reactions in which \( H_2O_2 \) acts as a reducing agent.