The compound that can work both as oxidising and reducing agent is

Options

A. `KMnO_(4)`
B. `H_(2)O_(2)`
C. `BaO_(2)`
D. `K_(2)Cr_(2)O_(7)`

Explanation

To determine the compound that can act both as an oxidizing agent and a reducing agent, we need to analyze the oxidation states of the given compounds and see if they can either gain or lose electrons.

### Step-by-step Solution:

1. **Understanding Oxidizing and Reducing Agents**:
- An **oxidizing agent** is a substance that gains electrons (is reduced) and, in the process, causes another substance to be oxidized (lose electrons).
- A **reducing agent** is a substance that loses electrons (is oxidized) and, in the process, causes another substance to be reduced (gain electrons).

2. **Analyzing the Given Compounds**:
- We will evaluate the oxidation states of the elements in each compound to see if they can act as both oxidizing and reducing agents.

3. **Evaluating KMnO4**:
- In KMnO4, potassium (K) is +1, oxygen (O) is -2, and manganese (Mn) is +7.
- Mn can only be reduced from +7 to +2. Thus, KMnO4 can only act as an oxidizing agent, not a reducing agent.

4. **Evaluating H2O2 (Hydrogen Peroxide)**:
- In H2O2, the oxidation state of hydrogen (H) is +1 and oxygen (O) is -1.
- Oxygen can change its oxidation state from -1 in H2O2 to 0 in O2 (gaining electrons, acting as an oxidizing agent) or from -1 to -2 in H2O (losing electrons, acting as a reducing agent).
- Therefore, H2O2 can act as both an oxidizing and a reducing agent.

5. **Evaluating BaO2 (Barium Peroxide)**:
- In BaO2, barium (Ba) is +2 and oxygen (O) is -1.
- Similar to H2O2, BaO2 can only act as an oxidizing agent because the oxidation state of Ba remains +2 and does not change to a lower state.

6. **Evaluating K2Cr2O7 (Potassium Dichromate)**:
- In K2Cr2O7, potassium (K) is +1, oxygen (O) is -2, and chromium (Cr) is +6.
- Chromium can only be reduced from +6 to +3, which means K2Cr2O7 can only act as an oxidizing agent.

7. **Conclusion**:
- The only compound among the given options that can act as both an oxidizing agent and a reducing agent is **H2O2 (Hydrogen Peroxide)**.

### Final Answer:
The compound that can work both as an oxidizing and reducing agent is **H2O2 (Hydrogen Peroxide)**.