Compared to aldehydes, how do alcohols differ in terms of boiling points?

Alcohols have higher boiling points than aldehydes primarily due to the presence of hydrogen bonding in alcohols. Alcohols contain a hydroxyl (-OH) functional group which allows them to form hydrogen bonds with other alcohol molecules. This strong intermolecular attraction significantly increases the amount of energy required to separate the molecules during the phase change from liquid to gas, resulting in higher boiling points.

In contrast, aldehydes have a carbonyl (C=O) functional group, which lacks the capacity to form hydrogen bonds as effectively as the hydroxyl group in alcohols. Although aldehydes can experience dipole-dipole interactions due to the polar carbonyl group, these interactions are weaker than the hydrogen bonding in alcohols. Consequently, aldehydes generally have lower boiling points compared to alcohols of similar molecular weight.

Thus, the strength and presence of hydrogen bonding in alcohols are the key factors that elevate their boiling points above those of aldehydes.