Question

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:

Options

• L₄ < L₃ < L₂ < L₁

• L₁ < L₃ < L₂ < L₄

• L₃ < L₂ < L₄ < L₁

• L₁ < L₂ < L₃ < L₄

Answer 1

L₁ < L₃ < L₂ < L₄

Explanation:

• L₁ absorbs red light (longest wavelength, weakest ligand).
• L₄ absorbs blue light (shortest wavelength, strongest ligand).

Thus, L₁ is the weakest and L₄ is the strongest, with L₃ and L₂ in between.