Question

Describe the process of simple distillation and fractional distillation. Explain the differences between the distillations and why each procedure works the way it does.

Answer 1

Distillation is a process which is used for purifying liquid as well as used for separating different liquids from a mixture. Designing of a distillation process depends on the difference of boiling points of liquids. Based on that, here are mainly two types of distillation

I. Simple distillation: When we have to separate two liquids having huge difference in boiling points then simple distillation technique is used. In this procees the liquid mixture is first heated in a flask (keeping the temperature little higher than the bpt of low boiling liquid) fitted with a condesor ( and a thermometer) which is attached with a receiver. The more volatile liquid (the liquid with the lower boiling point) will evaporate first and the vapor will pass throgh the condensor, whereby the liquid is condensed and can be collected in the receiving flask and taken out when liquid stopped coming from the liquid mixture.

Next, the remaining stuff in the is futher heated at higher temperature when the less volatile liquids will evaporate and collected in a receiver.

2. Fractional distillation: When we have to separate two or more liquids having close boiling points then fractional distillation technique is used. In this procees the liquid mixture is first heated in a flask (keeping the temperature little higher than the bpt of low boiling liquid) fitted with a fractionating column filled with glass or plastic beads which will serve as plates to improve the separation between the liquids having close boiling points. Fractinating column is connected with condesor which is attached with a receiver. The more volatile liquid will be condensed first and can be collected in the receiving flask and taken out.

Next, the remaining liquids will evaporate in the increasing order of their booiling point and can be collected in separate receiver.

.