Azeotropic Mixture

Azeotropic Mixture, solution that contains the same ratio of chemical constituents after distillation; boiling produces a vapour that has the same composition as the liquid, at a given pressure. The boiling point remains constant during distillation. The most common example is a solution of 4.43 per cent water and 95.57 per cent ethanol. Constituents of such mixtures cannot be separated by ordinary distillation, but addition of another chemical may make this possible—as in the addition of benzene to the above alcohol/water solution.