figures for it! Important conclusion Agitated mixtures of immiscible liquids will boil at a temperature lower than the boiling point of either of the pure liquids. Their combined vapour pressures are bound to reach the external pressure before the vapour pressure of either of the individual components get there. Steam distillation Notice that in the presence of water, phenylamine (or any other liquid which is immiscible with water) boils well below its normal boiling point. This has an important advantage in separating molecules like this from mixtures. Normal distillation of these liquids would need quite high temperatures. On the whole these tend to be big molecules we are talking about. Quite a lot of molecules of this sort will be broken up by heating at high temperatures. Distilling them in the presence of water avoids this by keeping the temperature low. That's what steam distillation achieves. Carrying out steam distillation We will carry on with the phenylamine example for now. During the preparation of phenylamine it is produced as a part of a mixture containing a solution of all sorts of inorganic compounds. It is removed from this by steam distillation. Steam is blown through the mixture and the water and phenylamine turn to vapour. This vapour can be condensed and collected. The steam can be generated by heating water in another flask (or something similar). As the hot steam passes through the mixture it condenses, releasing heat. This will be enough to boil the mixture of water and phenylamine