Question

what would you expect the vapor temperature to be after collecting 5ml of distillate in a mixture containing 10ml of acetone (bp 56C) and 10ml of water (bp 100C) for a fractional distillation? What would the vapor temperature be in a simple distillation?

Answer 1

Fractional Distillation.

Distillation is the process of heating a liquid to its boiling point, condensing the vapor by cooling, and collecting the liquid distillate. It is a technique for the purification of liquids and for the separation of liquid mixtures.

If a liquid mixture of acetone and water with composition 1:1 is heated to

boiling , then the vapor in equilibrium with it will have the composition with more acetone.

If this vapor is condensed and redistilled, the distillate will be much richer in acetone. As the distillation progresses, the mixture will gradually have less of acetone, the more of volatile component and its boiling point will gradually rise.

Consequently the distillate will contain a continually decreasing proportion

of the more volatile component, acetone until finally all has been collected and the

less volatile component, water is left as a residue.

So the temperature will be in the range of 50-70 ^oC while collecting 5 ml of the distillate.

Simple Distillation

For all practical purposes, separation of a liquid mixture into its components by a simple distillation is possible only when the boiling points of the components are 80 degrees or more apart.

In this case acetone and water will co-distill and temperature would be wide in range 80-100 ^oC.