Ionic mobility of which of the following alkali metal ions is lowest when aqueous solution of their salts are put under an electric field ?

Options

A. Na
B. K
C. Rb
D. Li

Answer

D

Explanation

Key concept More the extent of hydration lesser is the ionic mobility.
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 in the ionic mobility .