What is the correct order of increasing field strength for the ligands $NH_3$,$en$,$CN^-$,and $CO$?

The correct order for wavelengths of light absorbed in the complex ions $[CoCl(NH_{3})_{5}]^{2+}$, $[Co(NH_{3})_{6}]^{3+}$ and $[Co(CN)_{6}]^{3-}$ is

Which of the following will have maximum stabilization due to crystal field?

$A$ 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 $.........$

Which one of the following complexes has the highest magnitude of crystal field splitting energy $\left(\Delta_0\right)$?

The increasing order of the crystal field splitting power of some common ligands is