Hard Soft Water

The ease of adsorption of the hydrated alkali metal ions on ion-exchange resins follows the order:

1. $L{i}^{+}<K^{+}<N{a}^{+}<R{b}^{+}$

2. $R{b}^{+}<K^{+}<N{a}^{+}<L{i}^{+}$

3. $K^{+}<N{a}^{+}<R{b}^{+}<L{i}^{+}$

4. $N{a}^{+}<L{i}^{+}<K^{+}<R{b}^{+}$

The method used to remove the temporary hardness of water is-

1. Synthetic resins method

2. Calgon's method

3. Clark's method

4. Ion-exchange method