Question

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

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

Answer 1

Answer: (C)

Smaller ions are hydrated to greater extent.
As a result they had largest size and least mobility.
$\because L{i}^{+}$is smallest cation among
$L{i}^{+},N{a}^{+},C{s}^{+}$and $R{b}^{+}$.
It is most extensively hydrated.
Has least mobility in aqueous solution.