Distillation is a process of
separating the component substances from a liquid
mixture by selective
evaporation and
condensation. Distillation may result in essentially complete separation (nearly pure components), or it may be a partial separation that increases the concentration of selected components of the mixture. In either case the process exploits differences in the
volatility of mixture's components. In
industrial chemistry, distillation is a
unit operation of practically universal importance, but it is a physical separation process and not a
chemical reaction.