Question

How do you separate azeotropic mixtures?

Answer 1

Hint :Azeotropic mixtures are constant boiling mixtures. You need to break the azeotropes to separate them. This is because in the azeotropic mixture the vapor composition is the same as the liquid composition. Also for separating the mixtures azeotropic distillation can be done as normal distillation will not work.

Complete Step By Step Answer:
The azeotropic mixture is a mixture of liquids that has a constant boiling point. Or is a mixture of substances that has the same concentration of vapor and fluid phases. They are often referred to as constant boiling mixtures. The reason that they have a constant boiling point is that the vapor has the same composition as the liquid mixture. The boiling point of an azeotropic mixture may be higher or lower than that of any of its components.
The separation of azeotropic mixtures cannot be brought about by simple distillation or even fractional distillation. Also when an azeotropic mixture is boiled, the vapor has the same proportion of constituents as the unboiled mixture. And, therefore, such methods as adding a third component to change the volatility of the azeotrope or using two distillation columns operating at different pressures are used. This is called azeotropic distillation. This method separates the azeotropic mixtures. Also, we can break the azeotropes to separate the mixtures. This involves the separation method. For breaking, molecular sieves are used. The molecular sieves are treated with $ 96\% $ ethanol. This makes them anhydrous and they absorb the water from the mixtures. The sieves can be subsequently regenerated by dehydration using a vacuum oven.

Note :
There are many different types of azeotropic mixtures. Minimum boiling azeotrope or Negative Azeotrope, maximum boiling azeotrope or Positive Azeotrope, Heterogeneous and Homogeneous Azeotropes and Azeotropes Based on the Number of Constituents.