Question

What is the importance of Sandmeyer's reaction?

• A. To obtain R-I from R-Cl
• B. To obtain Ar-X by replacing diazo group of \(\text{AR-N}_2^+\text{-X}^-\) using \(\text{CuCl}\) / \(\text{HCl}\)
• C. To obtain R-F from R-Cl using AgF
• D. To obtain \(\text{R-CH}_2\text{-R}\) from R-CO-R using Zn-Hg / HCl

Hint:

Sandmeyer reaction replaces the diazonium group by Cl or Br using CuCl or CuBr.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
A benzene diazonium salt can be changed to an aryl halide in a Sandmeyer reaction. The diazonium group \(-\text{N}_2^+\) is replaced by \(-\text{Cl}\) or \(-\text{Br}\) using \(\text{CuCl/HCl}\) or \(\text{CuBr/HBr}\).

Step 2: Reaction:
\[ \text{Ar-N}_2^+\text{X}^- \xrightarrow{\text{CuCl/HCl}} \text{Ar-Cl} + \text{N}_2 \]

Step 3: Other options:
A (\(\text{R-Cl}\to\text{R-I}\)) is the Finkelstein reaction. C (using AgF) is the Swarts reaction. D (using Zn-Hg/HCl) is the Clemmensen reduction.

Final Answer:
Sandmeyer reaction gives Ar-X from the diazonium salt, option (B). \[ \boxed{\text{Ar-X from diazonium salt using CuCl/HCl}} \]