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Coordination Compounds

Question
CBSEENCH12010658

The octahedral complex of a metal ion M3+ with four Monodentate Ligands, L1, L2, L3 and L4 absorb wavelengths in the region of red, green, yellow and blue respectively. The increasing order of ligand strength of the four ligands is

  • L4< L3<L2<L1

  • L1<L3<L2<L4

  • L3<L2<L4<L1

  • L1<L2<L4<L3

Solution

B.

L1<L3<L2<L4

Ligand space field space strength
space space space space space space space space space space space space space space space space space space space space space space space proportional to Energy space of space light space absorbed
space space space space space space space space space space space space space space space space space space space space space space space proportional to space fraction numerator 1 over denominator Wavelength space of space light space absorbed end fraction
λ L1 L2 L3 L4
Absorbed light Red Green Yellow Blue
the wavelength of absorbed light decreases

Therefore, increasing order of energy of wavelengths abosrbed reflects greater extent of crystal - field splitting, hence higher field strength of the ligand.
Energy: Blue(L4)> Green (L2)> Yellow (L3) > Red (L1)