On heating gypsum at 373 K, we obtain:
Calcium sulphate hemihydrate
Baking soda
Washing soda
Calcium sulphate dihydrate
On heating gypsum it loses one and a half molecules of water and forms calcium sulphate hemihydrate also known as plaster of Paris
Question 04. Which of the following salts does not contain water of crystallization? (a) Blue vitriol (b) Baking soda (c) Washing soda (d) Gypsum