Question

Which of the following alkali metal ions has lowest ionic mobility in aqueous solution?

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

Answer 1

The correct option is D $L{i}^{+}$

As the size of ions increases the hydration of ions decreases. Higher the size of hydrated ion lower the ionic mobility. Among the alkali metal Li+ gets most hydrated in aqueous solution. Lithium has the lowest mobility.
The mobility of ions decrease in the order given below.

Hence, the correct option is D.