The reaction involving the treatment of benzene diazonium chloride with copper powder and HCl is treated as

Options

A. Sandmeyer's reaction
B. Gattermann's reaction
C. Ulmann's reaction
D. Kolbe's reaction

Explanation

To solve the question regarding the treatment of benzene diazonium chloride with copper powder and HCl, we can break it down into a step-by-step explanation.

### Step-by-Step Solution:

1. **Identify the Reactant**:
- The reactant in this reaction is benzene diazonium chloride. Its structure consists of a benzene ring (C6H5) attached to a diazonium group (N2^+) and a chloride ion (Cl^-).

2. **Understand the Reaction Conditions**:
- The reaction involves treating benzene diazonium chloride with copper powder (Cu) in the presence of hydrochloric acid (HCl).

3. **Reaction Mechanism**:
- When benzene diazonium chloride is treated with copper powder and HCl, nitrogen gas (N2) is released as a byproduct.
- The benzene diazonium ion (C6H5-N2^+) undergoes a reaction where the diazonium group is replaced by a chlorine atom (Cl), resulting in the formation of chlorobenzene (C6H5-Cl).

4. **Identify the Type of Reaction**:
- This specific reaction is classified as a halogenation reaction, where a halogen (in this case, chlorine) is introduced into an aromatic compound (benzene) through the substitution of the diazonium group.

5. **Name the Reaction**:
- The reaction is specifically known as **Gattermann's reaction**. This is a name reaction in organic chemistry that describes the formation of haloarenes from diazonium salts using copper and hydrochloric acid.

### Final Answer:
The reaction involving the treatment of benzene diazonium chloride with copper powder and HCl is treated as **Gattermann's reaction**.

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