Question

Why aldehyde and ketones have lower boiling point then carboxylic acids of comparable molecular mass

Answer 1

because acid consists of hydrogen bond in it

Answer 2

$\huge\textcolor{green}{\texttt{Answer :-}}$

Both alcohols and acids involve intermolecular hydrogen bonding. But no intermolecular H - bonding occur in aldehydes and ketones.

Therefore, attractive forces in aldehydes and ketones are lesser/weaker than acids and alcohols. Hence, lesser energy is required to break the attractive forces in aldehydes and ketones and thus they have low boiling points(low boiling point = less energy to break the attractive forces).