Question

What is meant by the water of crystallization? Give examples of salts with water of crystallization, and their uses.

Answer 1

Water of crystallization is a fixed number of water molecules present in the crystal structure. It's called water of crystallization. 

1. Alum (Potash alum - K₂SO₄.Al₂(SO₄)₃.24H₂O)
2. Borax (Na₂B₄O₇.10H₂O)
3. Epsom salt (Magnesium sulphate - MgSO₄.7H₂O)
4. Barium chloride (BaCl₂.2H₂O)
5. Sodium sulphate (Glauber’s salt Na₂SO₄.10H₂O)
6. Blue vitriol (CuSO₄.5H₂O)

Uses:

1. Alum: Alum and burnt alum is used in medicines. In the paper industry, alum is used to give shine to the paper. Alum is used to stop bleeding from wound. Alum is used in the process of purification of water.

2. Borax: Borax is used in the cosmetic industry to make lotions, shampoos and cold creams. It is used to remove the stain on clothes in a laundry. In the laboratory with the help of borax bead test, basic elements from the coloured salts are determined.

3. Epsom salt: Epsom salt is used in the manufacture of fertilizers and also to enhance the green colour of plants and vegetables. It is used in the manufacture of purgative medicines. It is used as body scrub. It is added in bath water (salt bath) to relieve muscle pain.
4. Barium chloride: It is used in the purification of brine solution. (saturated sodium chloride solution). It is used in the waste water management. It is used in the paper industry and also used in the dye industry, ceramics, oil purification and pesticides.
5. Sodium sulphate: It is used in the preparation of detergents. It is used to make paper pulp in paper industry and also used in the dye in the dye industry. It is used to make mild purgatives.

6. Blue vitriol: It is used in the blood test to diagnose anaemia. Blue vitriol and slaked lime are used in the Bordeaux mixture, which is used as a fungicide on fruits.