Which of these has the lowest boiling point?

Options

A. `2`-Methylpentane
B. `3`-Methylpentane
C. `2,2`-Dimethylbutane
D. `2,3`-dimethylbutane

Answer

C

Explanation

With branching, the shape of the molecule tends to approach that of a sphere and as this happens, the surface area decreases. As a result, intermolecular forces become weaker and are overcome at a lower temperature. For equal number of branches, the more symmetrical the molecule, the higher the boiling point `(bp)`.
Order of bp:`underset(63^(@)C)((2)) gt underset(60^(@)C)((1)) gtunderset(58^(@)C)((4)) gt underset(50^(@)C)((3))`