Question

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

• A. $K^{+}<{Na+Rb}^{+}<{Li}^{+}$
• B. ${Na}^{+}<{{Li}^{+}+K}^{+}<{Rb}^{+}$
• C. ${Li}^{+}<{K^{+}+Na}^{+}<{Rb}^{+}$
• D. ${Rb}^{+}<{K^{+}+Na}^{+}<{Li}^{+}$

Answer 1

Answer: (D)

${Rb}^{+}<{K^{+}+Na}^{+}<{Li}^{+}$

Ease of adsorption of the hydrated alkali metal ions on an ion-exchange resin decreases as the size of alkali metal ion increases.

Since the order of the size of alkali metal ion follows the order-

${Li}^{+}<{Na}^{+}<K^{+}<{Rb}^{+}$

Therefore, the ease of adsorption follows the order-

${Rb}^{+}<K^{+}<{Na}^{+}<{Li}^{+}$