Applications of simple distillation:
i. It is used for the preparation of distilled water and water for injection.
ii. Preparation of many volatile oils and aromatic water.
iii. Purification of organic solvent.
iv. Preparation official compound like spirit of nitrous ether and aromatic spirit of ammonia.
v. To separate volatile and non volatile solvents.
Principle of fractional distillation:
When substance dissolved in liquid, the vapour pressure of liquid is lowered.
The pressure exerted by each liquid in the mixture is known as partial pressure.
Since complete separation is not obtained in simple distillation, fractional distillation is used.
In fractional distillation, fractionating column is used which is fitted between distillation flask and condenser. Fractionating column is used for continuous separation of two miscible liquids.
The vapours formed are allowed to pass through fractionating column where a part of the vapour is condensed and while returning to still comes into an intimate contact with rising vapour resulting in further fractionation of the liquid being distilled.
The liquid with higher boiling point is condensed first and vapour becomes richer with the liquid having the lower boiling point which gets condensed in a condenser.