Discuss various steps involved in crystallisation.

Explanation

The various steps involved in crystallisation are as follows:
i) Preparation of the solution : The solution is prepared by dissolving the organic compound in a suitable solvent.
Choice of solvent: The important conditions for solvent are given below:
a) The organic substance should be soluble in a solvent.
b) The solvent should crystallise on cooling.
c) The solvent should not dissolve the impurities.
ii) Filteration of the solution: The above prepared solution is filtered through the filter paper.Now, filterate solution containing insoluble component remains on the filter paper (residue) and soluble component (filterate) is collected in a beaker.
iii) Crystallisation: In this step, filterate is allowed to stand undisturbed for some time. After sometime, crystals of the compound are formed.
iv) Separation of the crystals : In this step, crystals formed are separated from the liquid by filteration.
v) Drying of crystals : The crystals formed are dried by pressing in between the folds of filter paper.