Question

The ion having highest mobility in aqueous solution is

• A. $B{e}^{2+}$
• B. $M{g}^{2+}$
• C. $C{a}^{2+}$
• D. $B{a}^{2+}$

Answer 1

The correct option is D $B{a}^{2+}$

On going down the group the size of metal ion increase so hydration energy decreases. Since $B{a}^{2+}$ is the heaviest ion it is least hydrated. As a result, its size of hydrated ion becomes lesser than any other hydrated alkaline earth metal cation and hence has the highest ionic mobility.