Distillation is a process that can separate two liquids using what?

Distillation separates two liquids that have significantly different vapor pressures.

The usual process uses heat to evaporate the gas with the higher vapor pressure. The gaseous form of the liquid is moved to a different container, where it is cooled, causing the gas to condense back into a liquid.

In practical application, there is a limit to how completely two substances can be separated using distillation, because some of the substance with a lower vapor pressure will always evaporate along with the substance with higher vapor pressure.