Question

How does hydration energy of metal ion lead to change in reduction potential?

Answer 1

Answer:

Explanation:

As Lithium is smaller in size, it has high ionization energy. Thus, Li has greater tendency to lose electrons in solution than other alkali metals. Hence, Li is the strongest reducing agent. Thus, the reason for large reducing power of Li is due to it's high Hydration Energy.

Answer 2

Small Size and High Ionization Enthalpy for Lithium

Explanation:

One of the heat changes that are involved in the calculation of electrode potential is enthalpy of hydration. $Li^+$ being small in size has very high enthalpy of hydration.

• -3.05 V is the Standard reduction Potential for $Li^+/Li$

• Caesium being strongest Reducing Agent but in gaseous state.

• In aqueous solution $Cs^+$ is less hydrated and contributes to a lesser extent to the electrode potential calculation.

• High Ionization Enthalpy with small size for Lithium.  

• The ability to lose electrons in solution,is what being adhered to Lithium, but in solution, as compared to other alkali's. This ability makes Lithium to be strongest reducing agent.

Thus, the abnormally large reducing power of Li is due to its large hydration energy.