The correct order of the mobility of the alkali metal ions in aqueous solution is:

Step-by-step solution

As Charge density hydration. Therefore hydrated size of Li ⁺ is large and having less mobility and down the group degree of hydration decreases. So, among alkali metal ions, lithium has the lowest mobility. Rb ⁺> K ⁺> Na ⁺> Li ⁺ Related Theory The magnitude of hydration enthalpy depends on the charge density of the ions. The charge density is more for smaller ions and hence the smaller ions have higher values of hydration enthalpy. The higher the charge density the higher will be the force of attraction between the