Question

Consider the following reaction,
\[{{C}_{6}}{{H}_{5}}N{{O}_{2}}\xrightarrow{Sn/HCl}X\xrightarrow{{{C}_{6}}{{H}_{5}}COCl}Y+HCl\]
What is Y?
A. Acetanilide
B. Benzanilide
C. Azobenzene
D. Hydrazobenzene

Answer 1

Hint: When nitrobenzenes are treated with a mixture of tin and concentrated hydrochloric acid, the $-N{{O}_{2}}$ group present over the nitrobenzene will get reduced by the amine group. So, you will get your compound X and now try to figure out what product will be formed when an amine reacts with benzoyl chloride.

Complete step by step solution:
Given that,
\[{{C}_{6}}{{H}_{5}}N{{O}_{2}}\xrightarrow{Sn/HCl}X\xrightarrow{{{C}_{6}}{{H}_{5}}COCl}Y+HCl\]
Where \[{{C}_{6}}{{H}_{5}}N{{O}_{2}}\]is known as nitrobenzene and nitrobenzene is being treated with a mixture of tin and hydrochloric acid thereby forming compound X which we have to find out. Further, compound X is being reacted with \[{{C}_{6}}{{H}_{5}}COCl\], which we know as benzoyl chloride and the reaction between them forms a compound Y, which we have to figure out.
So, when nitrobenzene is treated with a mixture of tin and concentrated hydrochloric acid, the nitro group present in the reactant gets reduced to amine giving phenylamine or aniline. The reaction is shown below:
\[{{C}_{6}}{{H}_{5}}N{{O}_{2}}\xrightarrow{Sn/HCl}{{C}_{6}}{{H}_{5}}N{{H}_{2}}\]
Thus, the compound formed by the treatment of nitrobenzene and tin is aniline which is X as per the given question. And, now we have to find out what product will be formed when aniline is reacted with benzoyl chloride as per the question.
We, know that when a primary amine gets react with benzoyl chloride i.e. \[{{C}_{6}}{{H}_{5}}COCl\] , it will undergo benzoylation (according to Shcotten Baumann reaction) forming an amide and eliminating hydrochloric acid. The reaction is shown below,
${{C}_{6}}{{H}_{5}}N{{H}_{2}}\xrightarrow{{{C}_{6}}{{H}_{5}}COCl}{{C}_{6}}{{H}_{5}}NHCO{{C}_{6}}{{H}_{5}}+HCl$
So, the compound Y is formed from the above reaction which is an amide and is known as benzamide with chemical formula ${{C}_{6}}{{H}_{5}}CONH{{C}_{6}}{{H}_{5}}$.

Hence, the correct option is B.

Note: Schotten Baumann reaction and its condition where acetyl chloride is used, are usually used in the synthesis of synthetic capsaicin and phenethylamine. Some concepts used in the reaction are also used in the Fischer synthesis of peptides. So, it can be noted that this reaction plays an important role in organic chemistry. Further, remember while writing equations consider what the reactants that are treated with and so on you can know what type of reactions it will undergo.