Question

How do we get a pure substance from crystallization? What is the exact procedure for crystallization?

Answer 1

For your first question:
1. Is crystallization is better than evaporation?
Yes. Crystallization is better technique to get pure substances than evaporation. Because we are getting pure sample by crystallization while in evaporation we will get a solid with all impurties in solution like mud, organic matter etc.
2. Can we have crystallization for all substances?
It can be used for the substances for which we can change the solubility by adding reagents or changing conditions. Nearly all the solids solubility can be changed by changing conditions. So every crystalline solid substances can be crystallised. This means the method is not applicable for amorphous solids.