Explain with equation, what is noticed when permanent hard water is treated with

(a) slaked lime

(b) washing soda

What is permutit method, how can it be used for softening hard water ?

Explain:

(a) The use of lead pipes for drinking water supply is being discontinued.

(b) Chalk hills dissolve in rain water.

(c) Hard water is unfit for boilers.

(d) Iron chloride forms a saturated solution when exposed to the atmosphere.

(e) A bottle containing concentrated H₂SO₄ should be stoppered.

The following figure shows the solubility curves of NaCl, KNO₃ and hydrated calcium sulphate.

(a) Identify and label the curves with the salt it represents.

(b) State the factors on which the solubility depends.

(c) Solubility of which salt(s) shows :

(i) Endothermic process

(ii) Exothermic process?