Question

Arrange the following alkanes in increasing order of their boiling points.

• A. $C_5{H}_{12}$
• B. $C_7{H}_{{16}^{}}$
• C. $C_{10}{H}_{22}$
• D. $C_{13}{H}_{28}$

Answer 1

As the number of carbon atoms increases, surface area of the molecules increases. This increases the intermolecular van der Waals forces of attraction.
Thus, more energy is required to overcome these forces and move the molecules apart to convert into gases.
Hence, the boiling point of the given alkanes increases in the given order:$C_5{H}_{12}<C_7{H}_{16}<C_{10}{H}_{22}<C_{13}{H}_{28}$