Question

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

• A. $K^{+}<N{a}^{+}<R{b}^{+}<L{i}^{+}$
• B. $R{b}^{+}<K^{+}<N{a}^{+}<L{i}^{+}$
• C. $N{a}^{+}<L{i}^{+}<K^{+}<R{b}^{+}$
• D. $L{i}^{+}<K^{+}<N{a}^{+}<R{b}^{+}$

Answer 1

The correct option is B $R{b}^{+}<K^{+}<N{a}^{+}<L{i}^{+}$

The ease of adsorption of hydrated metal ions depends on the size of the hydrated ion. As the size increases, the ease of adsorption also increases.

Size of hydrated ion decreases as the size of the alkali metal ions increases.

Since, the order of size of alkali metal ions is
$L{i}^{+}<K^{+}<N{a}^{+}<R{b}^{+}$

The ease of adsorption follows the order
$R{b}^{+}<K^{+}<N{a}^{+}<L{i}^{+}$

Hence, option (a) is correct.