Question

Which of the following cannot be prepared by Sandmeyer’s reaction?
(i) Chlorobenzene
(ii) Bromobenzene
(iii) Iodobenzene
(iv) Fluorobenzene

• A. $(i)$ and $(ii)$
• B. $(ii)$ and $(iii)$
• C. $(iii)$ and $(iv)$
• D. $(i)$ and $(iv)$

Answer 1

Answer: (B)

* In case of (iii) Iodobenzene different reagents as KI used to obtain the product because it cannot be formed in presence of $Cu ( I )$ (Iodine being less reactive than other halogens)

* And for (iv) Fluoro-benzene it cannot be formed by this reaction due to the high reactivity of Fluorine the reaction $b / w F$ and benzene and rigorous and highly explosive.
The other 2 options (i) Chlorobenzene (ii) Bromobenzene can be formed by this reaction.