Question

Arrange the following compounds in increasing order of boiling point.
Propan - 1- ol, butan - 1 - ol, butan - 2 - ol, pentan - 1 - ol
(a) Propan-1-ol, butan-2-ol, butan-1-ol, pentan-1-ol
(b) Propan-1-ol, butan-1-ol, butan-2-ol, pentan-1-ol
(c) Pentan-1-ol, butan-2-ol, butan-1-ol, propan-1-ol
(d) Pentan-1-ol, butan-1-ol, butan-2-ol, propan-1-ol

Answer 1

Answer is (B) since 2 factors should be looked into.

First, boiling point depends on no. of carbons. More the carbons, more the boiling point(since more bonds of C-C have to be broken).

Secondly, look into the surface area of the molecule. Straight chain compounds has less area than branched chain compounds. And branched chain compounds have less area than aromatic compounds.

So, between butan1ol and butan2ol, more branched is butan2ol. That's why the answer should be (B).

Cheers.