Question

Give a brief description of the principles of distillation.

Answer 1

Hint: Simple distillation is generally used to purify liquids. This method is used for those liquids which are sufficiently stable at their boiling points and which contain non-volatile impurities.

Complete step by step answer: The process involves the conversion of a liquid into vapour by heating followed by condensation of the vapour thus produced by cooling is known as distillation. This method is based on the principle that at constant pressure every pure liquid boils at a definite temperature called the boiling point. It is used for the purification of those liquids which boil without decomposition provided the impurities are non-volatile. This method is applied for the purification when the two liquids differ in the boiling points by 30K – 50K. It is used for the purification of simple organic liquids such as benzene, ethanol, acetone, chloroform, carbon tetrachloride, toluene, xylenes, etc.
The procedure of simple distillation is that when the flask is heated, the temperature rises gradually and the liquid starts boiling when its vapour pressure becomes equal to atmospheric pressure. These vapours as they pass through condensers are condensed and the liquid which distils at constant temperature is collected in a receiver and a pure liquid is obtained.
Additional information: Application of distillation is as follows:
Purification of drugs obtained from the chemical process.
It is used for the refining of petroleum products.

Note: The plant that performs distillation is called a distillery and the apparatus used to perform distillation is called a still. Initially, distillation is believed to have been used to make perfumes.