Question

In the given reaction, \(X\) is ________.

• A. Benzene
• B. Chlorobenzene
• C. 1,2-Dichlorobenzene
• D. 1,3,5-Trichlorobenzene

Hint:

Aryl diazonium salt with \(CuCl/HCl\) gives chlorobenzene. This is Sandmeyer reaction.

Answer 1

The Correct Option is B

Concept:
This reaction is based on the conversion of an aryl diazonium salt into chlorobenzene. When benzene diazonium chloride reacts with \(CuCl/HCl\), the diazonium group is replaced by chlorine. This reaction is known as the Sandmeyer reaction.

Step 1: Understand the diazonium salt reaction.
Aryl diazonium salt has the group: \[ -N_2^+Cl^- \] This group can be replaced by different groups using suitable reagents.

Step 2: Use \(CuCl/HCl\).
With \(CuCl/HCl\), the diazonium group is replaced by chlorine: \[ C_6H_5N_2^+Cl^- \xrightarrow{CuCl/HCl} C_6H_5Cl \] The product: \[ C_6H_5Cl \] is chlorobenzene.

Step 3: Check the options.
Option (A) benzene would form if diazonium group is replaced by hydrogen.
Option (B) chlorobenzene is correct.
Option (C) 1,2-dichlorobenzene would require two chlorine atoms.
Option (D) 1,3,5-trichlorobenzene would require three chlorine atoms. Hence, the correct answer is: \[ \boxed{(B)\ \text{Chlorobenzene}} \]