Which physical property distinguishes alkanes from alcohols?

The correct choice highlights that alkanes are generally non-polar and exhibit lower solubility in water compared to alcohols. This distinction arises from the molecular structure of both classes of compounds. Alkanes consist solely of carbon and hydrogen atoms arranged in a hydrocarbon framework, which results in a non-polar character due to the symmetrical distribution of electron density. As a result, they do not interact favorably with polar solvents like water and tend to be insoluble or only slightly soluble.

On the other hand, alcohols possess a hydroxyl (–OH) functional group, which is polar. This functional group allows alcohols to form hydrogen bonds with water molecules, significantly increasing their solubility in water relative to alkanes. Therefore, the marked difference in polarities and solubility characteristics serves as a key physical property that distinguishes alkanes from alcohols.

Understanding this distinction is crucial when studying organic compounds, as it impacts not only solubility but also reactivity and the behavior of these substances in various chemical processes.