Carboxylic acids have higher boiling points than aldehydes, ketones and even alcohols of comparable molecular mass. It is due to their:

Carboxylic acids form very stable intermolecular hydrogen-bonded dimers. Even in the vapor phase, these dimers persist. This extensive hydrogen bonding requires significantly more energy to break, leading to higher boiling points compared to alcohols (which also H-bond but less extensively) and carbonyl compounds (which only have dipole-dipole interactions).