Question

I. Diazonium salts are very good intermediates for the introduction of $F,Cl,Br,I,CN,OH,N{O}_2$ groups into the aromatic ring.
II. Aryl fluorides and iodides can be prepared by direct halogenation.
III. Cyano group cannot be introduced by nucleophilic substitution of chlorine in chlorobenzene.
IV. The replacement of diazo group by other groups is helpful in preparing those substituted aromatic compounds which cannot be prepared by direct substitution in benzene or substituted benzene.
Select the incorrect statements,

• A. $I$ and $II$
• B. $II$ and $III$
• C. $III$ and $IV$
• D. $I$ and $IV$

Answer 1

Answer: (B)

Diazonium salts are very good intermediates for the introduction of $-F,Cl,Br,I,CN,OH,N{O}_2$ groups into the aromatic ring. Aryl fluorides and iodides cannot be introduced by nucleophilic substitution of chlorine in chlorobenzene but cyanobenzene can be easily obtained from diazonium salt.
Replacement of diazo groups is helpful in preparing those substituted aromatic compounds which cannot be prepared by direct substitution in benzene or substituted benzene.