Give one chemical test to distinguish between chlorobenzene and benzyl chloride ?

Answer

To distinguish between chlorobenzene and benzyl chloride, we can perform a chemical test using silver nitrate (AgNO3) solution. Here’s a step-by-step solution:

### Step-by-Step Solution:

1. **Identify the Compounds**:
- Chlorobenzene (C6H5Cl) has a chlorine atom directly attached to a benzene ring.
- Benzyl chloride (C6H5CH2Cl) has a chlorine atom attached to a carbon that is connected to a benzene ring.

2. **Prepare the Test**:
- Take two separate test tubes.
- In one test tube, add a few drops of chlorobenzene.
- In the other test tube, add a few drops of benzyl chloride.

3. **Add Silver Nitrate Solution**:
- To both test tubes, add an equal amount of silver nitrate (AgNO3) solution.

4. **Observe the Reaction**:
- **For Benzyl Chloride**: A white precipitate of silver chloride (AgCl) will form. This is because the chlorine atom in benzyl chloride can be displaced, forming a stable benzyl carbocation, which allows Ag+ ions to react with Cl- ions to form AgCl.
- **For Chlorobenzene**: No precipitate will form. This is because the chlorine atom in chlorobenzene is part of a stable aromatic system and cannot be easily displaced.

5. **Conclusion**:
- The formation of a white precipitate in the test tube with benzyl chloride indicates its presence, while the absence of precipitate in the test tube with chlorobenzene confirms that it is chlorobenzene.

### Summary of the Test:
- **Chemical Test**: Reaction with AgNO3 solution.
- **Observation**:
- Precipitate forms with benzyl chloride (indicating the presence of benzyl chloride).
- No precipitate forms with chlorobenzene (indicating the presence of chlorobenzene).