Ionic mobility of which of the following alkali metal ions is lowest when an aqueous solution of their salts are put under an electric field?
(a) Na (b) K
(c) Rb (d) Li
(d) Key Idea More the extent of hydration, lesser is the ionic mobility.
Ionic mobility of alkali metal ions is lowest when aqueous solutions of their salts are put under an electric field. In all the alkali metals, Li+ ion is smallest thus, extent of hydration is maximum in Li+ ion i.e. The dissolution of Li+ in water occurs and get hydrated. Smaller the size of a cation, greater is the extent of hydration and lesser is the ionic mobility.