Question

The number of structural isomers possible from the molecular formula $C_3{H}_{9}N$ is:

• A. 2
• B. 3
• C. 4
• D. 5

Answer 1

The correct option is C 4

$\text{Degree of unsaturation}=(C+1)-\frac{H}{2}-\frac{X}{2}+\frac{N}{2}$
For $C_3{H}_{9}N$,
$\text{Degree of unsaturation}=(3+1)-\frac{9}{2}+\frac{1}{2}$
= 4 - 4 = 0
Therefore, no unsaturation (no double bond, triple bond and ring structure) in given molecular formula.
Hence, the possible structural isomers will be

Therefore, the number of structural isomers possible from molecular formula $C_3{H}_{9}N$ are 4.