They collide with other molecules which are not yet in violent motion, and in the end some of the molecules attain such high velocities that they burst through the surface film of the liquid. They thus escape from the liquid as a gas. When they encounter the molecules of a colder medium, these escaped molecules part with some of their kinetic energy, coalesce, and finally form water droplets. In chemical technology this process is performed in a distilling apparatus which, if it is of great size, is known as a distilling column. In this way, distillation is used for separating evaporable substances from non-evaporable ones, or separating substances that evaporate easily from others that evaporate less easily.
Distillation is therefore a process for the separation of substances according to their volatility.
Distillation is one of the most important methods of purifying volatile substances and has been practiced for thousands of years. They are employed more particularly in the petroleum industry for the production of power gases, fuels, lubricating oils, etc., but distillation is, for example, also an essential process in the manufacture of alcohol. We hope you found the information contained on these pages informative and enjoyable. This site was created just for fun. We don't sell any of these items or know who does.