Question

What is meant by “Water of Crystallization” of a substance? - Describe an activity to show the water of crystallization?

SCERT Telangana Class 10 General Science Ch Acid Bases and Salts

Answer 1

Water of Crystallization is the fixed no. of molecules which are present in one formula unit of salt.
Activity-
Aim-To show the water of crystallization
Materials required-Copper sulphate,Bunsen Burner,China dish.
Procedure-Put some copper sulphate crystals on china dish and heat it with Bunsen burner.
Observation-The blue colour crystals of Copper sulphate changes to white powder on removal of 5 molecules of water of crystallization.
Equation-CuSO₄.5H₂O⇒CuSO₄
Conclusion-This shows water of crystallization.

Answer 2

The number of water molecules chemically combined in a definite molecular proportion with the salt in its crystalline state is called Water of Crystallization. A substance containing water of crystalzation is known as a hydrate or a hydrous substance. When this substance is heated, the water gets expelled and then the salt is said to have become anhydrous.

CuSO4  . 5H2 O  (crystalline copper sulphate also known as blue vitriol ) when  heated   becomes  white powdery CuSO4 (anhydrous copper sulphate).