DISTILLATION

When a solution of solid in liquid is heated, the liquid will evaporates. The hot vapor that formed can de condensed back to liquid again on a cold surface. We called this method DISTILLATION. Distillation is used for separating a solvent from a solution. We called the liquid collected a distillate.

Evaporation + Condensation = DISTILLATION

A way is to recover water from a salt solution. The solution is heated and the stream is to be condensed back to water. The solute and solvent can both be collected.

Before heating, there are a few very small pieces of pumice stone (antibumping granules) added into the solution. This is used to ensure even boiling. Otherwise, the solution might become so vigorously agitated which some of it might spurt into the collecting vessel before vaporization.

The bulb of the thermometer is to be placed above the liquid surface. In order to record the temperature of the vapor distilled over and collected. In this case, it will provide the boiling point.

Another set-up for distillation uses a condenser. This set-up condenses the steam even more efficiently. The condenser consists of two tubes, one inside the other. Cool water will pass through the outer tube and steam from the solution will pass through the inner tube.

The water supply enters the condenser at the lower opening, leaving the upper opening to get a better cooling effect.