Question

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

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

Answer 1

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

In an aqueous solution, the ionic mobility of metal ions decreases with increase in charge density (Charge/Size).
The order of charge density for the given ions is-
$L{i}^{+}>N{a}^{+}>C{s}^{+}>R{b}^{+}$

Hence the ion having the lowest ionic mobility is $L{i}^{+}$.