Question

The correct order of ionic mobility for the following ions in aqueous solution is:

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

Answer 1

The correct option is A $C{s}^{+}$ > $R{b}^{+}$ > $K^{+}$ > $N{a}^{+}$ > $L{i}^{+}$

The correct order is:
$C{s}^{+}$ > $R{b}^{+}$ > $K^{+}$ > $N{a}^{+}$ > $L{i}^{+}$
because ions are hydrated in the solution. Smaller the size in gaseous phase, more is the hydration and more will be the hydrated size and hence, it moves slowly. $C{s}^{+}$ is least hydrated and its hydrated radius is smaller than the radius of hydrated $L{i}^{+}$.