sir plzz.. explain what is water of crystallization?

common salt ie, NaCl looks solid when viwed... but it has certain H₂O molecules present in it... and hence it forms crystals..

So, while crystals of salts are hydrated and has H₂O molecules... and these molecules are called water of crystalization..

The water molecules which form part of the structure of a crystal ( of a salt) are called water of crystallisation. The salts which contain water of crystallisation are called hydrated salts. Every hydrated salt has a fixed number of molecules of water of crystallisation in its one formula unit.Ex- CuSO₄.5H₂O, Na₂CO₃.10H₂O etc.