Question

Aromatic nitriles $(ArCN)$ are not prepared by reaction:

• A. $Ar X+ KCN$
• B. $ArN _{2}^{+} X^-+ CuCN$
• C. $ArCONH _{2}+ P _{2} O _{5}$
• D. $ArCONH _{2}+ SOCl _{2}$

Answer 1

Answer: (A)

Aryl halides $(Ar X)$ does not show nucleophilic substitution reaction as they have strong $C -X$ bond.
Above reaction involve nucleophilic substitution reaction. Thus $ArCN$ cannot be prepared by reaction of $Ar X$ and $KCN$.

Only alkyl halide can be prepared by this method.
$ C _{6} H _{5} CONH _{2} \xrightarrow[\text{Heat}]{P_2O_5} \underset{\text{benzene carbonitrile}}{C_6H_5CN + H_2O}$
$C_6H_5CONH_2 \xrightarrow{SO_2Cl} C_6H_5CN + SO_2 + 2HCl$
$Ar\overset{+}{N_2}\bar{X} + :\bar{C}N \xrightarrow[KCl]{CuCN} ArCN + N_2 + \bar{X} :$