Why does the blue colour of copper sulphate pentahydrate changes on heating? 

State one relevant reason for the following:

• Hydrated copper sulphate crystals turn white on heating.

Give one phrase for the following statement:

The property by which certain hydrated salts, when left exposed to atmosphere, lose their water of crystallization and crumble into powder.

The property by which a crystal loses its water of crystallization is called

One mole of a sample of hydrated sodium sulphide contains $162 \mathrm{g}$ of water of crystallisation. What is the correct formula of this compound?

Washing soda contains _____ molecules of water of crystallisation. 

Note - Answer in words.

The number of water molecules present in a molecule of copper sulphate crystal is 

X is a hydrate of calcium. On heating, it gives an another hydrate, Y which is used for setting fractured bones. The ratio of water molecules in X and Y (X: Y) is

White vitriol is chemically _____.

(A) ${\mathrm{ZnSO}}_4.7{\mathrm{H}}_2\mathrm{O}$                  (B) ${\mathrm{CuSO}}_4.5{\mathrm{H}}_2\mathrm{O}$                  (C) ${\mathrm{FeSO}}_4.7{\mathrm{H}}_2\mathrm{O}$

Enter your correct answer as A, B or C.

Anhydrous substance lack their _____ of crystallisation.