Three complexes, (I), (II) and (III) absorb light in the visible region. The correct order of the wavelength of light absorbed by them is:

Question

Three complexes,  (I),  (II) and  (III) absorb light in the visible region. The correct order of the wavelength of light absorbed by them is:

Canvas Classes · Accepted Answer

Strategy:
 The wavelength of light absorbed is inversely proportional to the crystal field splitting energy (), which depends on the strength of the ligands. Stronger ligands cause higher  and shorter wavelength of absorption.

Step 1: Evaluate ligand field strengths
All complexes contain Cobalt.
- (I) : Contains one weak field  ligand and five . Weakest field overall among the three.
- (II) : Contains one  and five .  is a stronger field ligand than .
- (III) : Contains six  ligands. Strongest

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