Question

The mobility of metal ions in an aqueous medium $(L{i}^{⨁},N{a}^{⨁},K^{⨁},R{b}^{⨁})$ in an electric field, follows the order:

• A. $L{i}^{⨁}>N{a}^{⨁}>K^{⨁}>R{b}^{⨁}$
• B. $R{b}^{⨁}>N{a}^{⨁}=K^{⨁}>L{i}^{⨁}$
• C. $L{i}^{⨁}<N{a}^{⨁}<K^{⨁}<R{b}^{⨁}$
• D. $N{a}^{⨁}=K^{⨁}>R{b}^{⨁}>L{i}^{⨁}$

Answer 1

The correct option is C $L{i}^{⨁}<N{a}^{⨁}<K^{⨁}<R{b}^{⨁}$

Mobility of ions is inversely proportional to the size of hydrated ions. The order of size of hydrated ions is $L{i}^{⨁}>N{a}^{⨁}>K^{⨁}>R{b}^{⨁}$ due to high charge density.
Therefore order of mobility is: $L{i}^{⨁}<N{a}^{⨁}<K^{⨁}<R{b}^{⨁}$