Chloro benzene can be prepared by reacting benzene diazonium chloride with

Options

A. HCl
B. `Cu_2Cl_2//HCl`
C. `Cl_2//AlCl_3`
D. `NHO_2`

Explanation

To prepare chlorobenzene from benzene diazonium chloride, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**: The starting material is benzene diazonium chloride, which has the formula C6H5N2Cl. This compound contains a benzene ring, a diazonium group (N2^+), and a chloride ion (Cl^-).

2. **Understand the Reaction**: To convert benzene diazonium chloride to chlorobenzene (C6H5Cl), we need to replace the diazonium group with a chlorine atom. This transformation is typically achieved through a reaction known as the Sandmeyer reaction.

3. **Select the Appropriate Reagent**: The reagent required for this reaction is cuprous chloride (CuCl) in the presence of hydrochloric acid (HCl). The combination of CuCl and HCl facilitates the substitution of the diazonium group with a chlorine atom.

4. **Write the Reaction**: The overall reaction can be represented as:
\[ C6H5N2Cl + CuCl + HCl \rightarrow C6H5Cl + N2 + CuCl2 \]
In this reaction, the diazonium group (N2) is released as a gas, and chlorobenzene is formed.

5. **Conclusion**: Therefore, to prepare chlorobenzene from benzene diazonium chloride, the correct reagent to use is cuprous chloride (CuCl) along with hydrochloric acid (HCl).

### Final Answer:
Chlorobenzene can be prepared by reacting benzene diazonium chloride with cuprous chloride (CuCl) in the presence of hydrochloric acid (HCl).

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