Define water of crystallisation with two examples. How will you prove their existence in the examples given by you ?

Explanation

The fixed number of water molecules present in one formula unit of a salt is water of crystalisation.
The water of crystalisation in the salt is responsible for the colour and the crystal structure of the salts. When a coloured salt crystal is subjected to heat, it loses both its colour and crystalline structure due to loss of water. This proves their existence in salts.