Softening of Hard Water

(i) The hard water is made to pass through a column packed with zeolite (sodium aluminium silicate)

(ii) Ca­­­⁺⁺, Mg⁺⁺ ions which are responsible for hardness, get adsorbed on zeolite, exchanging sodium ions.

(iii) The exhausted zeolite is regenerated with 10% of sodium chloride solution.