Homoleptic octahedral complexes of a metal ion ′ M 3 + ′ with three monodentate ligands L 1 ,…

Homoleptic octahedral complexes of a metal ion ′M3+′ with three monodentate ligands L1, L2 and L3 absorb wavelengths in the region of green, blue and red respectively. The increasing order of the ligand strength is:
  1. L3>L1>L2.
  2. L1>L2>L3.
  3. L2>L1>L3.
  4. L3>L2>L1.

Solution

Observed order of wavelengths, λabs =L3>L1>L2.

(Red light has highest wavelength of 700 nm while blue is the shortest with a wavelength of about 480 nm)

So, ∆0 (strength of ligands) order  will be L2>L1>L3.

(As ∆0 α 1λabs )

Hence, order will be L2>L1>L3.

Therefore, Strength of ligand ∝∆Absorption.

Asked in: JEE Main 2019 (09 Jan Shift 2)

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