# How many structural isomers can be drawn for pentane (C5H12)?

Mar 2, 2018

Are there not THREE structural isomers with formula ${C}_{5} {H}_{12}$?

#### Explanation:

$\left(i\right)$ ${\text{H"_3"CCH"_2"CH"_2"CH"_2"CH}}_{3}$ $\text{n-pentane}$.

$\left(i i\right)$ ${\text{H"_3"CCH"("CH"_3)"CH"_2"CH}}_{3}$ $\text{isopentane}$.

$\left(i i i\right)$ "H"_3"CC"("CH"_3)_3 $\text{neopentane}$.

The normal boiling points of these isomers are respectively: $36.1$ ""^@C; $27.7$ ""^@C; $9.5$ ""^@C.

Why does the length of the carbon chain apparently affect the boiling point?