Propan-2-ol (b.p. 82ºC) Propan-1-ol (b.p. 98ºC)

 

The effect of shape on the boiling point of compounds can be illustrated by comparing these two molecules. Both molecules exhibit hydrogen bonding and they both have the same Mr. Consequently any difference in b.p. must be due to the shape.

Propan -2- ol is more spherical as can be appreciated by right clicking on the two images and applying the space-fill option (Display --> Space fill --> Van de Waals radii)