Question

Why is order of boiling point of alcohols is 3°>2°>1° ?

Answer 1

A primary alcohol is an alcohol which has the hydroxyl group connected to a primary carbon atom. It can also be defined as a molecule containing a “–CH₂OH” group.^[1] In contrast, a secondary alcohol has a formula “–CHROH” and a tertiary alcohol has a formula “–CR₂OH”, where “R” indicates a carbon-containing group.

The boiling point of alcohols also increase as the length of hydrocarbon chain increases.
The differences in boiling point between primary, secondary, and tertiary alcohols can be subtle. Generally, the more “exposed” the hydroxyl group, the more other OH groups it will be able to interact with, and the higher the boiling point. The isomers of butanol are a perfect example. See how the primary alcohols (1-butanol and 2-methyl-1-propanol) have higher boiling points than the secondary alcohol (2-butanol) which has a higher boiling point than the tertiary alcohol (t-butanol).

So the correct order will be 1>2>3

primary alcohol has more boiling point than others