Which one of the following has the minimum boiling point :

Options

A. 1-butene
B. 1-butyne
C. n-butane
D. Isobutane

Answer

D

Explanation

Among the isomeric alkanes, the normal isomer has a higher boiling point than the branched chain isomer. The greater the branching of the chain, the lower is the boiling point. The n-alkane have larger surface area in comparison to branched chain isomer (as the shape approaches that of a sphere in the branched chain isomers). Thus, intermolecular forces are weaker in branched chain isomers, therefore they have lower boiling point in comparison to straight chain isomers.