How do the boiling points of carbonyl compounds compare to similar alkanes?

The boiling points of carbonyl compounds are higher than those of similar alkanes due to the presence of a polar carbonyl group (C=O) in their molecular structure. This functional group introduces significant dipole-dipole interactions among the molecules of carbonyl compounds. These interactions are stronger than the dispersive forces that mainly govern the boiling points of alkanes, which are nonpolar molecules.

As a result, when comparing carbonyl compounds, such as aldehydes or ketones, with alkanes that have the same number of carbon atoms, the carbonyl compounds typically exhibit higher boiling points because it requires more energy to overcome the intermolecular forces associated with the polar carbonyl group. Thus, the presence of this functional group is key in raising the boiling points of these compounds compared to their alkane counterparts.