Which of the following has the highest tendency to give the following reaction.

${\mathrm{M}}_{\left(\mathrm{g}\right)}^{+}\underset{\mathrm{medium}}{\overset{\mathrm{aqueous}}{\to }}{\mathrm{M}}_{\left(\mathrm{aq}.\right)}^{+}$

${\mathrm{M}}_{\left(\mathrm{g}\right)}^{+}\underset{\mathrm{medium}}{\overset{\mathrm{aqueous}}{\to }}{\mathrm{M}}_{\left(\mathrm{aq}.\right)}^{+}$

${\mathrm{Li}}_{\left(\mathrm{g}\right)}^{+}$  has the highest tendency to give the ${\mathrm{Li}}_{\left(\mathrm{aq}.\right)}^{+}$
Reason:

Li⁺ ion is smaller in size. Hence, it possesses greater nuclear charge So attraction of water molecules by Li⁺ ion increases. Therefore, degree of hydration increases, and hence, hydration energy increases. It is an Exothermic process
NOTE:
The amount of energy released during the hydration of 1 mole of ions is called hydration energy.
Stability of  ${\mathrm{M}}_{\left(\mathrm{aq}\right)}^{+}$ $\propto$ hydraction energy