Correct Answer – C
The standard reduction electrode potential, `E^(@)(M^(+)//M)`, which measures the reducing power in aqueous solutions represents the overally change `M(s)toM^(+)(aq.)+e^(-)` its negative value is favoured by lower sublimation enthalpy. All alkali metals have similar ionization enthalpies. Li has the highest ionization enthalpy as well as the highest hydration enthalpy as well as the highest hydration enthalpy. However, energy reqruied to ionize Li is more than comprensated by the large amount of energy released during the hydration of `Li^(+)`(g) ion.Thus, the highest hydration enthalpy (among all alkali metal ions) of Li accounts for high negative `E^(@)` and its high reducing power.