#ligand substitution

Which complex would turn colorless if all its ligands were replaced by CN−?

[Ni(H₂O)6]2+ (Ni₂+, d8) is colored (green) due to d-d transitions with weak field H₂O. With strong field CN− (e.g., [Ni(CN)6]4−), it becomes low spin (diamagnetic), no d-d transitions, colorless.

Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Colour and Magnetic Properties and Stability and Importance