What characteristic do alcohols exhibit due to their hydroxyl groups?

Alcohols contain hydroxyl groups (-OH), which significantly influence their physical properties. One key characteristic resulting from the presence of these hydroxyl groups is that alcohols exhibit higher boiling points compared to similar aliphatic hydrocarbons that lack such functional groups. This phenomenon occurs because the hydroxyl group is polar and capable of forming hydrogen bonds between alcohol molecules, which requires more energy to overcome during the phase transition from liquid to gas.

In contrast, hydrocarbons primarily exhibit London dispersion forces, which are weaker than hydrogen bonds. As a result, alcohols will have substantially higher boiling points than their non-polar counterparts of similar molecular weight. This property makes alcohols unique in terms of their boiling points relative to other compounds of similar size.

The other options do not accurately describe a characteristic attributed to alcohols due to their hydroxyl groups. For instance, while alcohols can be flammable, their flammability varies widely and is more a function of molecular structure and chain length rather than solely the presence of the hydroxyl group. Solubility in water tends to increase with the presence of hydroxyl groups, making alcohols generally more soluble than non-polar compounds. Lastly, reactivity with metals does not primarily stem from the hydroxyl group