Distillation

Distillation is a process that can be used to separate a pure liquid from a mixture of liquids. It works when the liquids have different boiling points. Distillation is commonly used to separate ethanol - the alcohol in alcoholic drinks - from water.

Distillation process to separate ethanol from water

Step 1 - water and ethanol solution are heated

Step 2 - the ethanol evaporates first, cools, then condenses

Step 3 - the water left evaporates, cools, then condenses

The mixture is heated in a flask. Ethanol has a lower boiling point than water so it evaporates first. The ethanol vapour is then cooled and condensed inside the condenser to form a pure liquid. The thermometer shows the boiling point of the pure ethanol liquid. When all the ethanol has evaporated from the solution, the temperature rises and the water evaporates.

This is the sequence of events in distillation:

heating → evaporating → cooling → condensing