Question

The correct order of the mobility of the alkali metal ions. In aqueous solultion is

Options

• K⁺ > Rb⁺ > Na⁺ > Li⁺

• Rb⁺ > K⁺ > Na⁺ > Li⁺

• Li⁺ > Na⁺ > K⁺ > Rb⁺

• Na⁺ > K⁺ > Na⁺ > Li⁺

Answer 1

Rb⁺ > K⁺ > Na⁺ > Li⁺

Explanation:

As we move down the group, the hydration enthalpies of alkali metal ions decrease with increasing ionic radii.

As a result, the greater the ionic mobility in an aqueous solution, the smaller the mass of hydrated species.

As a result, the order of ionic mobility is Rb⁺ > K⁺ > Na⁺ > Li⁺.