Question

$E^{\circ}_{Mn^{3+}/Mn^{2+}}$ is highly positive than that of $E^{\circ}_{Cr^{3+}/Cr^{2+}}$ or $E^{\circ}_{Fe^{3+}/Fe^{2+}}$ because

• A. $Mn^{2+}\, (d^5)$ can be easily oxidised to $Mn^{3+}\,(d^4)$ due to low ionisation enthalpy
• B. third ionisation 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 ionisation enthalpy of Mn is higher than third ionisation enthalpy

Answer 1

Answer: (B)

Correct answer is (b) third ionisation enthalpy of $Mn$ is much larger due to stable half filled $d^5$ electronic configuration of $Mn^{2+}$