Question

In the reaction series: $C_6{H}_{5}Cl\underset{C{u}_{2}O,{200}^{o}C}{\overset{N{H}_3}{\to }}X;X\underset{{0-5}^{0}C}{\overset{{HNO}_2}{\to }}Z;X+Z\to A$, the number of $\sigma$ and $\pi$ bonds in $A$ are:

• A. $25$$\sigma$ and $6$$\pi$
• B. $25\sigma$ and $7\pi$
• C. $27\sigma$ and $7\pi$
• D. $27\sigma$ and $6\pi$

Answer 1

The correct option is C $27\sigma$ and $7\pi$

Nucleophilic substitution of chloro-benzene with ammonia gives aniline.

$C_6{H}_{5}Cl\underset{{Cu}_{2}O,{200}^{0}C}{\overset{{NH}_3}{\to }}\underset{X}{C_6{H}_{5}N{H}_2}+HCl$
Diazotization of aniline gives benzene diazonium chloride.

$\underset{X}{C_6{H}_{5}N{H}_2}\underset{{0-5}^{0}C}{\overset{{HNO}_2}{\to }}\underset{Z}{C_6{H}_5{N}_{2}Cl}$
Azo coupling of aniline with benzenediazonium chloride gives p-aminoazobenzene.

$\underset{X}{C_6{H}_{5}N{H}_2}+\underset{Z}{C_6{H}_5{N}_{2}Cl}\to \underset{A}{C_6{H}_5-N=N-C_6{H}_4-N{H}_2}$
The number of $\sigma$ and $\pi$ bonds in $C_6{H}_5-N=N-C_6{H}_4-N{H}_2$ are $27$$\sigma$ and $7$$\pi$.

Hence, the correct option is C.