Reagent capable of converting benzene diazonium chloride to benzene is

Options

A. Water
B. Acid
C. `H_(3)PO_(2)`
D. HCl

Answer

To solve the question of which reagent can convert benzene diazonium chloride to benzene, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Benzene Diazonium Chloride**:
- Benzene diazonium chloride has the formula C6H5N2Cl. It consists of a benzene ring (C6H5) attached to a diazonium group (N2+) and a chloride ion (Cl-).

2. **Recognizing the Reaction**:
- The conversion of benzene diazonium chloride to benzene involves the replacement of the diazonium group (N2) with a hydrogen atom (H). This is a reduction reaction.

3. **Identifying Suitable Reducing Agents**:
- Common reducing agents that can facilitate this reaction include:
- Phosphorus acid (H3PO2)
- Ethanol (C2H5OH)
- Other mild reducing agents.

4. **Evaluating the Given Options**:
- The problem states we have four reagents to choose from. We need to identify which of these can effectively reduce benzene diazonium chloride to benzene.

5. **Selecting the Correct Reagent**:
- Among the common reducing agents, H3PO2 (phosphorus acid) is known to effectively reduce benzene diazonium salts to benzene.
- Ethanol is also a mild reducing agent, but if it is not listed among the options, we focus on H3PO2.

6. **Conclusion**:
- Therefore, the reagent capable of converting benzene diazonium chloride to benzene is **H3PO2**.

### Final Answer:
The reagent capable of converting benzene diazonium chloride to benzene is **H3PO2** (option C).