In acidic medium ,` H_(2)O_(2)` acts as a reducing agent in its reaction with `:`

Options

A. `FeSO_(4)`
B. `KMnO_(4)`
C. `K_(2)MnO_(4)`
D. `K_(4)[Fe(CN)_(6)]`

Explanation

To determine in which reactions H2O2 acts as a reducing agent in acidic medium, we will analyze each option step by step.

### Step 1: Analyze the first option - FeSO4
1. **Write the reaction**:
\[ \text{FeSO}_4 + \text{H}_2\text{O}_2 \rightarrow \text{Fe}_2(\text{SO}_4)_3 + \text{Fe(OH)}_3 \]
2. **Determine oxidation states**:
- In FeSO4, Fe is +2.
- In Fe2(SO4)3, Fe is +3.
3. **Identify changes**:
- Fe is oxidized from +2 to +3 (loss of electrons).
4. **Conclusion**: H2O2 is acting as an oxidizing agent, not a reducing agent.

### Step 2: Analyze the second option - KMnO4
1. **Write the reaction**:
\[ \text{KMnO}_4 + \text{H}_2\text{O}_2 \rightarrow \text{K}^+ + \text{Mn}^{2+} + 8\text{H}_2\text{O} + 5\text{O}_2 \]
2. **Determine oxidation states**:
- In KMnO4, Mn is +7.
- In the products, Mn is +2.
3. **Identify changes**:
- Mn is reduced from +7 to +2 (gain of electrons).
4. **Conclusion**: H2O2 is acting as a reducing agent.

### Step 3: Analyze the third option - K2MnO4
1. **Write the reaction**:
\[ \text{K}_2\text{MnO}_4 + \text{H}_2\text{O}_2 \rightarrow \text{MnO}_2 + \text{O}_2 + \text{KOH} \]
2. **Determine oxidation states**:
- In K2MnO4, Mn is +6.
- In MnO2, Mn is +4.
3. **Identify changes**:
- Mn is reduced from +6 to +4 (gain of electrons).
4. **Conclusion**: H2O2 is acting as a reducing agent.

### Step 4: Analyze the fourth option - K4[Fe(CN)6]
1. **Write the reaction**:
\[ \text{K}_4[\text{Fe(CN)}_6] + \text{H}_2\text{O}_2 \rightarrow \text{K}_3[\text{Fe(CN)}_6] + \text{K}_2\text{SO}_4 + \text{H}_2\text{O} \]
2. **Determine oxidation states**:
- In K4[Fe(CN)6], Fe is +2.
- In K3[Fe(CN)6], Fe is +3.
3. **Identify changes**:
- Fe is oxidized from +2 to +3 (loss of electrons).
4. **Conclusion**: H2O2 is acting as an oxidizing agent.

### Final Conclusion:
H2O2 acts as a reducing agent in the reactions with KMnO4 and K2MnO4. Therefore, the correct options are:
- **B (KMnO4)**
- **C (K2MnO4)**