Question

The sequence of ionic mobility in aqueous solution is $\mathrm{\_\_\_\_\_\_\_}$

• A. ${\mathrm{K}}^{+}>{\mathrm{Na}}^{+}>{\mathrm{Rb}}^{+}>{\mathrm{Cs}}^{+}$
• B. ${\mathrm{K}}^{+}>{\mathrm{Na}}^{+}>{\mathrm{Cs}}^{+}>{\mathrm{Rb}}^{+}$
• C. ${\mathrm{Cs}}^{+}>{\mathrm{Rb}}^{+}>{\mathrm{K}}^{+}>{\mathrm{Na}}^{+}$
• D. ${\mathrm{Na}}^{+}>{\mathrm{Rb}}^{+}>{\mathrm{Cs}}^{+}>{\mathrm{K}}^{+}$

Answer 1

The correct option is C

${\mathrm{Cs}}^{+}>{\mathrm{Rb}}^{+}>{\mathrm{K}}^{+}>{\mathrm{Na}}^{+}$

Explanation for the correct option:

(c ) ${\mathrm{Cs}}^{+}>{\mathrm{Rb}}^{+}>{\mathrm{K}}^{+}>{\mathrm{Na}}^{+}$

• The smaller the cation, the greater the hydration and effective size, and the lower the mobility of the aqueous solution.
• Degree of Hydration decreases with increasing atomic size in alkali metal in aqueous solution, but the order of ionic mobility reverses.
• ${\mathrm{Cs}}^{+}>{\mathrm{Rb}}^{+}>{\mathrm{K}}^{+}>{\mathrm{Na}}^{+}$
• Hence this option is correct.

Hence the correct option is (c ) ${\mathrm{Cs}}^{+}>{\mathrm{Rb}}^{+}>{\mathrm{K}}^{+}>{\mathrm{Na}}^{+}$