The ionic mobility of alkali metal ions in aqueous solution is maximum for:

Options

A. `Na^(+)`
B. `Rb^(+)`
C. `Li^(+)`
D. `K^(+)`

Answer

B

Explanation

Smaller the effective size of the hydrated species higher the ionic mobilit. Since the degree of hydration of alkali metal ions decreases on moving down the group on account of decrease of charge density `Rb^(+)` has the maximum ionic mobility.