Question

Which has the more boiling point 2 methyl pentane or 3 methyl pentane? Give reason.

Answer 1

The explanation is as follows.

The more branched an alkane molecule is the lower its boiling point. This is due to the less contact area available and hence less vanderwall forces.
3-methyl is slightly more compacted, compared to 2-methyl which is just a little more elongated, which leads to a greater density.
Also,
B.P. of 2-methylpentane:60C
B.P. of 3-methylpentane:63.3C

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