Question

The compound formed by the action of ${\text{HCl}}$ on acetamide is:
A. ${\text{C}}{{\text{H}}_3}{\text{CO}}{{\text{N}}^ \oplus }{{\text{H}}_3}{\text{C}}{{\text{l}}^ - }$
B. ${\text{C}}{{\text{H}}_3}{\text{COCl}}$
C. ${\text{C}}{{\text{H}}_3}{\text{COOH}}$
D. ${\text{C}}{{\text{H}}_3}{\text{CONHCl}}$

Answer 1

Hint: Amides are derived from carboxylic acids. A carboxylic acid contains the ${\text{ - COOH}}$ group, and in an amide, the ${\text{ - OH}}$ part of that group is replaced by an ${\text{ - N}}{{\text{H}}_2}$ group. Acetamide is prepared from acetic acid.

Complete step by step answer:
Amides are classified to primary, secondary and tertiary, depending on how many hydrogen atoms are attached to the nitrogen atom. Acetamide is a primary amide. A primary amide is an amide in which two hydrogen atoms are bonded to the amide nitrogen atom. Such amides are also called unsubstituted amides.
The reaction between ${\text{HCl}}$ and amide is called amide hydrolysis. In amide hydrolysis, the bond between the carbonyl carbon atom and the nitrogen is broken, and free acid and free amine are produced. Amide hydrolysis is catalyzed by acids, bases or certain enzymes; sustained heating is also often required. The general chemical equation of amide hydrolysis is given below:
${\text{R}} - {\text{CO}} - {\text{NH}} - {\text{R}}' + {{\text{H}}_2}{\text{O}} \to {\text{R}} - {\text{COOH}} + {\text{R}}' - {\text{N}}{{\text{H}}_2}$
Amide hydrolysis can be of two types-acidic hydrolysis and basic hydrolysis. When amide hydrolysis occurs in the presence of acid with water, it is called acidic hydrolysis. It convert the amide to amine salt and carboxylic acid. The reaction is given below:
${\text{R}} - {\text{CO}} - {\text{NH}} - {\text{R}}' + {\text{HCl}}\xrightarrow{{{{\text{H}}_2}{\text{O}}}}{\text{R}} - {\text{COOH}} + {\text{R}}' - {{\text{H}}_3}{{\text{N}}^ + }{\text{C}}{{\text{l}}^ - }$
Here, in this problem, water molecules are not used. Only ${\text{HCl}}$ is used. Thus there is no formation of carboxylic acid.
Thus the compound formed by the action of ${\text{HCl}}$ with acetamide is ${\text{C}}{{\text{H}}_3}{\text{CO}}{{\text{N}}^ \oplus }{{\text{H}}_3}{\text{C}}{{\text{l}}^ - }$. Thus the reaction is:
${\text{C}}{{\text{H}}_3} - {\text{CO}} - {\text{N}}{{\text{H}}_2} + {\text{HCl}} \to {\text{C}}{{\text{H}}_3} - {\text{CO}}{{\text{H}}_3}{{\text{N}}^ + }{\text{C}}{{\text{l}}^ - }$

Hence the correct option is A.

Note:
When basic hydrolysis of amide occurs in the presence of base, it is called basic hydrolysis. It converts the amide to amine and carboxylic acid salt. The reaction is given below:
${\text{R}} - {\text{CO}} - {\text{NH}} - {\text{R}}' + {\text{NaOH}} \to {\text{R}} - {\text{CO}}{{\text{O}}^ - }{\text{N}}{{\text{a}}^ + } + {\text{R}}' - {\text{N}}{{\text{H}}_2}$
Amide Carboxylic salt Amine