Why ester have low boiling point than coressponding acid?

Answer 1

Since esters no longer have a hydrogen atom bonded to the oxygen as a carboxylic acid does, they are not able to hydrogen bond. This means intermolecular forces are much weaker and they boil at lower temperatures.

Answer 2

Esters have lower boiling points than their corresponding acids because they have weaker intermolecular forces. Esters have only London dispersion forces and dipole-dipole interactions, while acids also have stronger hydrogen bonding. This results in esters requiring less energy to overcome these forces and boil compared to acids.