Question

In the given reaction sequence:
\[{{C}_{6}}{{H}_{5}}N{{O}_{2}}\xrightarrow{Sn/HCl}A\xrightarrow{NaN{{O}_{2}}+HCl}B\xrightarrow{CuCN/HCN}C\xrightarrow[{}]{{{H}_{2}}O/{{H}^{\oplus }}}D\]
Which one is not correct?
1) A is \[{{C}_{6}}{{H}_{5}}N{{H}_{2}}\]
2) B is \[{{C}_{6}}{{H}_{5}}-{{N}^{\oplus }}=N-C{{l}^{-}}\]
3) C is \[{{C}_{6}}{{H}_{5}}C{{H}_{2}}CN\]
4) D is \[{{C}_{6}}{{H}_{5}}COOH\]

Answer 1

Hint: The nitro compounds are formed by the process of nitration by mixing the organic compound with the nitric acid. These nitro compounds are polar in nature. The organic compounds such as toluene and benzene are affected during the nitration only when they are treated with the mixture of sulphuric acid and nitric acid at the temperature of \[{{100}^{o}}\]or less.

Complete step-by-step answer:
When nitro benzene is reacted with Sn/HCl it undergoes reduction because this is a strong reducing agent and the reduced product is formed. The product formed is known as aniline. And when the aniline formed as product A is reacted with \[NaN{{O}_{2}}+HCl\], a diazonium salt is formed which is unstable and carries some charge as product B. so the name of the product B is benzene diazonium chloride. When the product B that is benzene diazonium chloride is reacted with CuCN/HCN, the nitrogen gas is released and the formation of benzonitrile takes place as product C. When the benzonitrile undergoes hydrolysis the formation of benzoic acid takes place as the product D. The reactions for them are the following:
 \[{{C}_{6}}{{H}_{5}}N{{O}_{2}}\xrightarrow{Sn/HCl}{{C}_{6}}{{H}_{5}}N{{H}_{2}}\xrightarrow{NaN{{O}_{2}}+HCl}{{C}_{6}}{{H}_{5}}-{{N}^{\oplus }}=N-Cl\]
\[{{C}_{6}}{{H}_{5}}-{{N}^{\oplus }}=N-C{{l}^{-}}\xrightarrow{CuCN/HCN}{{C}_{6}}{{H}_{5}}CN\xrightarrow[{}]{{{H}_{2}}O/{{H}^{\oplus }}}{{C}_{6}}{{H}_{5}}COOH\]
So option 1, option 2 and option 4 are correct but option 3 is incorrect because benzonitrile formation occurs instead of benzene cyanide.

So the correct option for this question is option ‘3’.

Note: Benzoic acid is the organic compound which exists as crystalline solid and colourless solid in normal conditions. It is a monoclinic structure with a faint pleasant odour. It has the tendency to get soluble in water, benzene and acetone. It is used in production of phenol and in manufacturing of ointments.