Question

Water of crystallization is the fixed number of water molecules present in the crystal of that salt. The chemical formula of hydrated copper sulphate is CuSO4.5H2O i.e., there are five water molecules present in one formula unit of copper sulphate. Therefore, water of crystallization of copper sulphate is 5.

Similarly, there are two water molecules present in one formula unit of gypsum (CaSO4.2H2O). Hence, water of crystallization of gypsum is 2.

however in hemihydrated Caso4 is known as POP it has half water of crystalization. Pl explain

Answer 1

When we are heating gypsum at 443 Kelvin one and a half of water molecules evaporate and the remaining half of the molecules remains inside the Caso4 itself hence we get pop in the form of hemihydrated Solution

Answer 2

When we are heating gypsum at 443 Kelvin one and a half of water molecules evaporate and the remaining half of the molecules remains inside the Caso4 itself hence we get pop in the form of hemihydrated Solution