Which of the following `n`-alkane is not a solid at room temperature?

Options

A. `CH_(3)(CH_(2))_(18)CH_(3)`
B. `CH_(3)CH_(2))_(17)CH_(3)`
C. `CH_(3)(CH_(2))_(16)CH_(3)`
D. `CH_(3)(CH_(2))_(15)CH_(3)`

Answer

D

Explanation

Intermolecular forces holding nonpolar or very weakly polar molecules of alkanes together ( dispersion or London forces) are very weak and are of very short range. They act only between the portions of different molecules. Within a homologus series(family), the larger the molecule and hence the larger its surface area the stronger the intermolecular forces. `n`-Alkanes `C_(18)` onwards are colorless solids at room temperature.