Question

Carboxylic acids have higher boiling points than those of ethers. Give reason.

Answer 1

1. In the liquid phase, carboxylic acids form a dimer in which two molecules are held by two hydrogen bonds.
2. Acidic hydrogen of one molecule forms a hydrogen bond with the carbonyl oxygen of the other molecule.
3. This doubles the size of the molecule resulting in an increase in intermolecular van der Waals forces, which in turn results in a high boiling point.
4. Therefore, carboxylic acids have higher boiling points than those of ethers of comparable mass.