Crystal field stabilization energy for complex $[Co(CN)_6]^{3-}$ will be

$A$ transition metal $(M)$ among $Mn, Cr, Co$ and $Fe$ has the highest standard electrode potential $(M^{3+} / M^{2+})$. It forms a metal complex of the type $[M(CN)_6]^{4-}$. The number of electrons present in the $e_g$ orbital of the complex is $.........$

State the limitations of crystal field theory $(CFT)$.

The correct increasing order for the wavelengths of absorption in the visible region for the complexes of $Co^{3+}$ is:

The correct order of the complexes $[Co(NH_3)_5(H_2O)]^{3+}$ $(A)$,$[Co(NH_3)_6]^{3+}$ $(B)$,$[Co(CN)_6]^{3-}$ $(C)$,and $[CoCl(NH_3)_5]^{2+}$ $(D)$ in terms of the wavelength of light absorbed is:

The hexaquo manganese $(II)$ ion contains five unpaired electrons,while the hexacyano manganese $(II)$ ion contains only one unpaired electron. Explain using Crystal Field Theory.