Give the principle, working and application of” Fractional distillation.
Principle of fractional distillation:
It differs from simple distillation in that Partial condensation of vapour is allowed to occur in a fractionating column through which the vapour must pass before reaching the condenser .
This column enables ascending vapour from the still to come in contact with the condensing vapour returning to still. This results in enrichment of the vapour in the more volatile component.
Working:
The mixture of miscible liquids is heated in the still. The vapours formed are allowed to pass through the fractionating column, where a part of the vapour is condensed & while returning to the still comes, into an intimate contact with the rising power.
This leads to further fractionation of the liquid being distilled.
The liquid with higher boiling point is condensed first & vapour becomes richer with the liquid having the lower boiling point which gets condensed in a condenser.
Applications of “ Fractional distillation “ are as follows :-
Alcohol is purified from the mixture of alcohol & water obtained from fermentation tank.
It is used for the separation of miscible liquids, such as alcohol & water, acetone & water, Chloroform & Benzene.