Question

Alkanamide which on Hofmann’s reaction gives 1-phenyl ethyl amine is
A) $2$-phenyl propanamide
B) $3$-phenyl propanamide
C) $2$-phenyl ethanamide
D) ${\text{N}}$- phenyl ethanamide

Answer 1

The full form of IUPAC is the International Union of Pure and Applied Chemistry. It is a World Wide organisation for the nomenclature of the new elements in the periodic table and chemical molecules. The IUPAC has certain rules and regulations for the naming of the organic compound. In that method only we named the organic molecules in World level. The naming of any organic molecule depends on the parent saturated hydrocarbon.

Complete answer:
We must know that Hoffmann’s reaction does nothing but convert amide to amine by using bromine in aqueous solution in this reaction, the product of amine will be obtained depending on the parent of the amide in the reaction. The product will get one carbon atom less than reactant.
The reaction is given below,

$2$-phenyl ethanamide is reacted with bromine in aqueous solution on Hofmann’s reaction to 1-phenyl ethyl amine.
According to the above discussion, we conclude $2$-phenyl ethanamide on Hofmann’s reaction gives 1-phenyl ethyl amine.
Hence, option A is not correct, because $2$-phenyl propanamide on Hofmann’s reaction does not give 1-phenyl ethyl amine.
Hence, option B is not correct, because $3$-phenyl propanamide on Hofmann’s reaction does not give 1-phenyl ethyl amine.
Hence, option C is correct, because $2$-phenyl ethanamide on Hofmann’s reaction gives 1-phenyl ethyl amine.
Hence, option D is not correct, because -phenyl ethanamide on Hofmann’s reaction does not give 1-phenyl ethyl amine.

Note:
We must have to know that the functional group of the molecule is very important for the naming time. If one molecule having more than one functional group means some priority list is also provided from IUPAC. If the number of substituent and functional group is dependent on the minimum number will come from the left side or right of the terminal carbon atom in the chain. The aldehyde functional group in the molecule ends with al. it is one of the IUPAC rules for the naming of functional groups.