Why is anhydrous CaCl₂ used in a desiccator. Name one substance which is 'efflorescent'.

Name a salt

(a) which contains water of crystallization

(b) which does not contain.

Explain the following observations :

(i) Washing-soda become coated with a white powder when left exposed to the atmosphere.

(ii) In the expression anhydrous copper sulphate, what is meant by 'anhydrous'.

(iii) Why is fused calcium chloride or conc. sulphuric acid used in a desiccator.

Complete the following : The solubility of a gas at constant pressure may be increased by decreasing the ……………