Question

$\text{C}{{\text{H}}_{3}}\text{CON}{{\text{H}}_{2}}$ and $\text{HCONHC}{{\text{H}}_{3}}$ are called:
A. Position isomers
B. Chain isomers
C. Tautomers
D. Functional isomers

Answer 1

Hint: The compounds have the same molecular formula but different arrangements of the atoms in space are called isomers.
In this case, the compounds have the same molecular formula but they differ in the functional group attached to the main chain of carbon atoms.

Complete step by step answer:
- The compounds which have the same molecular formula but different functional groups attached to it are called functional isomers.
- $\text{C}{{\text{H}}_{3}}\text{CON}{{\text{H}}_{2}}$ and $\text{HCONHC}{{\text{H}}_{3}}$ are called functional isomers.
- They have the same molecular formula that is ${{\text{C}}_{2}}{{\text{H}}_{5}}\text{NO}$.
- They differ in the functional groups attached.
- $\text{C}{{\text{H}}_{3}}\text{CON}{{\text{H}}_{2}}$, acetamide has the following structure:

The functional group is the primary amide ($\text{-CON}{{\text{H}}_{2}}$). If it is broken down, the functional groups are ketone and primary amine.
- $\text{HCONHC}{{\text{H}}_{3}}$, n-methyl formamide has the following structure:

The functional group is the secondary amide. If it is broken down, the functional groups are aldehyde and secondary amine.
So, the correct option is D.

Additional information:
Isomers can be divided into two types:
Constitutional isomers
Stereoisomers

Note: Chain isomers and isomers with the same molecular formula but different arrangement of branches of carbon.
Positional isomers are the isomers with the same molecular formula but attachment the functional groups in the different locations in the carbon chain.
Tautomers are the isomers of a compound that exist in equilibrium. The most common example of tautomer is keto-enol formation.
Keto-enol formation is one of the important basic mechanisms of organic chemistry.