The lower-molecular-weight alcohols are water-soluble, but above approximately 10 carbons, alcohols no longer will mix with water.

Their hydrocarbon tails then are large enough to dominate the -OH group.

Alcohols with longer hydrocarbon chains form a surface monolayer film at an air-water interface, as shown to the right.

This property of making films with long-chain molecules, half in and half out of the solution, will be important later with fatty acids and biological membranes.