Question

Differentiate between Evaporation and Distillation and explain the working and application of simple distillation.

Answer 1

Evaporation	Distillation:
1. Free escape of vapors from the surface of liquid below its boiling point. Evaporation takes place even at room temperature	1) Process of converting liquid into vapors by heating and reconverting again into liquid by condensing the vapors.
2) liquid is heated below its boiling point	2.Liquid its heated at its boiling point
3) Vapors are formed at the surface of the liquid	3.Vapours are formed throughout liquid
4) Vapors formed are not usually collected	4.Vapours formed are condensed and collected
5)Recovery of solvent is possible in few methods	5. Recovery of solvent is always done
6) used for the preparation of Conc. Liquid, Soft and dry extract.	6.Used for separation of volatile oil

Working of Simple Distillation: It involves simple equipment like an evaporating still, for vaporization of liquid, and condenser. Usually a glass assembly is used for this purpose. The distillation flask has a side arm, sloping downward to attach condenser and the liquid obtained is collected in the receiver. Small pieces of porcelain are added in the flask to avoid bumping of the liquid. Thermometer is fitted in the distillation flask to note and control the temperature. It is important because distillation of the various components occurs at different specific temperatures.

Applications of Simple Distillation :

1) It is used for the preparation of Distilled water and Water for Injection.

2) Many Volatile oils and aromatic water are prepared by simple distillation.

3) Organic solvents are purified by distillation.

4) Many official Compounds are prepared by distillation. E.g.: spirit of nitrous ether and aromatic spirit of ammonia.

5) Concentration of liquid and to separate non volatile solid from the volatile liquid such as alcohol and ether.