Question

The functional isomers of ethane nitrile are:
A. Ethyl carbylamine
B. Methane nitrile
C. Methyl carbylamine
D. Propane nitrile

Answer 1

Hint: Functional isomers are structural isomers that have the same molecular formula (that is, the same number of atoms of the same elements), but the atoms are connected in different ways so that the groupings are dissimilar. These groups of atoms are called functional groups.

Complete Step by step solution:
The functional group present in ethane nitrile is nitrile, the nitrile functional group is represented as $(-C\equiv N)$. The formula for ethane nitrile is ${{C}_{2}}{{H}_{3}}N$.
The functional group present in ethyl carbylamine is iso-cyanide and the formula for ethyl carbylamine is ${{C}_{3}}{{H}_{6}}N$.
The functional group present in methane nitrile is nitrile so ethane nitrile and methane nitrile cannot be functional isomers of each other.
The functional group present in methyl carbylamine is iso-cyanide and the formula for methyl carbylamine is ${{C}_{2}}{{H}_{3}}N$ similar to ethane nitrile.
The molecular formula for ethane nitrile and methyl carbylamine is the same but the functional group in both compounds is different hence ethane nitrile and methyl carbylamine are functional isomers of each other.
The functional group present in propane nitrile is nitrile so ethane nitrile and propane nitrile cannot be functional isomers of each other.

According to the above-mentioned points, we conclude that a correct answer is an option (C) methyl carbylamine.

Note: Don’t get confused between cyanide and isocyanide, Cyanide is CN whereas isocyanide is NC. Isocyanide is an organic compound with a functional group $(-N\equiv C)$. It is the isomer of the related cyanide $(-C\equiv N)$. A group is connected to the isocyanide group through the nitrogen atom, whereas in cyanide it is connected through a carbon atom $(-N\equiv C)$.