Question

$Eº_{Mn^{3 +}/Mn^{2 +}}$ is highly positive than that of $Eº_{Cr^{3 +}/Cr^{2 +}}$ or $Eº_{Fe^{3 +}/Fe^{2 +}}$ because

• A. $Mn^{2 +}(d^{5})$ can be easily oxidized to $Mn^{3 +}(d^{4})$ due to low ionization enthalpy.
• B. Third ionization enthalpy of Mn is much larger due to stable half filled $d^{5}$ electronic configuration of $Mn^{2 +}$
• C. $Mn^{3 +}$ is more stable than $Mn^{2 +}$ due to higher oxidation state
• D. Second ionization enthalpy of Mn is higher than thired ionization enthalpy

Answer 1

Answer: (B)

Third ionization enthalpy of Mn is much larger due to stable half filled $d^{5}$ electronic configuration of $Mn^{2 +}$

Answer 2

The third ionization energy of Mn required to change $Mn^{2 +}(d^{5})$ to $Mn^{3 +}(d^{4})$ is much larger due to stable half filled $d^{5}$electronic configuration.