Question

Explain why the branching of an alkane chain lower its boiling points?

Answer 1

The intermolecular force of attraction in between the alkane molecules are Van der waal forces. The strength of Van der waal forces depends on surface area of the molecule. Higher the surface area, higher will be the force of attraction and high will be the boiling points.
As we know branching reduces the surface area of the molecules, hence lower will be the force of attraction between the molecules and lesser will be the boiling point as compared to straight chain analogue.