Step 1: What sets boiling point.
Boiling point depends on how strongly the molecules hold on to each other through hydrogen bonding. The stronger and more extensive the hydrogen bonding, the higher the boiling point.
Step 2: Hydrogen bonding in carboxylic acids.
A carboxylic acid molecule has both an \(-OH\) (donor) and a \(C=O\) (acceptor). Two such molecules pair up using two hydrogen bonds at once, forming a stable cyclic dimer.
Step 3: Effect of the dimer.
Because the acid moves around as a dimer, it behaves like a molecule of double the mass, and breaking apart two strong hydrogen bonds needs a lot of energy.
Step 4: Hydrogen bonding in alcohols.
An alcohol has only one \(-OH\) group, so each molecule forms just one hydrogen bond with its neighbour. These chains are weaker and easier to break than the double-bonded acid dimers.
Step 5: Compare.
Since the acid forms stronger, double hydrogen bonds while the alcohol forms only single ones, the acid needs more heat to boil.
Answer: Carboxylic acids exist as stable hydrogen-bonded dimers held by two strong O-H...O bonds, so far more energy is needed to separate them than for alcohols, which form only single hydrogen bonds. Hence carboxylic acids have higher boiling points than alcohols of comparable molecular mass.