Give a brief account of Kala-azar.

Explanation

(i) Fractional distillation: This method is used to purify and separate liquids present in the mixture having their boiling point close to each other. The process of separation of the components in liquid mixture at their respective boiling points in the form of vapours and the subsequent condensation of those vapours is called fractional distillation. This method applied in distillation of petroleum, coal tar and crude oil.
(ii) Column chromatography:
(a) The principle behind chromatography is selective distribution of mixture of organic substances between two phases a stationary phase and a moving phase. The stationary phase can be a solid or liquid, while the moving phase is a liquid or a gas. When the stationary phase is a solid, the moving phase is a liquid or gas.
(b) If the stationary phase is solid, the basis is adsorption, and when it is a liquid, the basis is partition
(c) Chromatography is defined as a technique for the separation of a mixture brought about by differential movement of the individual component through porous medium under the influence of moving solvent.
(d) In column chromatography, the above principle is carried out in a long glass column