Chemistry - Coordination Chemistry Question with Solution | TestHub

We know $\mathrm{E}=\mathrm{h}v=\frac{\mathrm{hC}}{\lambda }$
$\mathrm{E}\propto \frac{1}{\lambda }$
Here all Co in +3 oxidation state.
So, as the ligand field strength $\uparrow ,\mathrm{CFSE}\uparrow$
Order of field strength of ligand :
$\mathrm{CN}>{\mathrm{NH}}_3>{\mathrm{H}}_2\mathrm{O}>{\mathrm{Cl}}^{-}$
CFSE order : $\mathrm{C}>\mathrm{B}>\mathrm{A}>\mathrm{D}$
Wavelength order: $\mathrm{D}>\mathrm{A}>\mathrm{B}>\mathrm{C}$