Which compound acts as oxidising agent only?

Options

A. `SO_(2)`
B. `H_(2)S`
C. `H_(2)SO_(4)`
D. `HNO_(2)`

Answer

To determine which compound acts as an oxidizing agent only from the given options (SO2, H2S, H2SO4, HNO2), we need to analyze the oxidation states of the elements in each compound and their ability to gain or lose electrons.

### Step-by-Step Solution:

1. **Understanding Oxidizing Agents**:
- An oxidizing agent is a substance that gains electrons (is reduced) while causing another substance to lose electrons (is oxidized).

2. **Analyzing SO2**:
- In SO2, the oxidation state of sulfur (S) is +4 (O is -2).
- Sulfur can either be reduced to -2 or oxidized to +6.
- Since it can both gain and lose electrons, SO2 can act as both an oxidizing agent and a reducing agent.

3. **Analyzing H2S**:
- In H2S, the oxidation state of sulfur is -2 (H is +1).
- Sulfur cannot gain any more electrons (it is already at its lowest oxidation state).
- Therefore, H2S can only lose electrons and act as a reducing agent.

4. **Analyzing H2SO4**:
- In H2SO4, the oxidation state of sulfur is +6 (H is +1, O is -2).
- Sulfur is already at its highest oxidation state and cannot lose electrons.
- It can only gain electrons, thus it acts solely as an oxidizing agent.

5. **Analyzing HNO2**:
- In HNO2, the oxidation state of nitrogen (N) is +3 (H is +1, O is -2).
- Nitrogen can either be reduced to -3 or oxidized to +5.
- Hence, HNO2 can act as both an oxidizing agent and a reducing agent.

6. **Conclusion**:
- The only compound that acts solely as an oxidizing agent is H2SO4, as it cannot be reduced further and can only oxidize other substances.

### Final Answer:
**H2SO4** is the compound that acts as an oxidizing agent only.