Question

The octahedral complex of a metal ion m3+ with four monodentate ligands l1, l2, l3 and l4 absorb wavelength in the region of red, green, yellow and blue, respectively. The increasing order of ligand strength of the four ligands is

Answer 1

Δ(CFSE)∝1λ(wavelength)  

[∆ or CFSE ∝ strength of ligands]

Hence, order of strength of ligand is :

L1(red)<L2(yellow)<L3(green)<L4(blue)