Answer: Weakening of the bond trans to a strong trans-influencing ligand (strong sigma donor weakens trans bond).
- A Weakening of the bond trans to a strong trans-influencing ligand (strong sigma donor weakens trans bond)
- B A simple shift in the colour the square planar complex visibly displays under usual circumstances according to most researchers
- C A measurable change observed in the complex's overall magnetic moment instead in the majority of cases studied
- D The complete absence of any measurable effect whatsoever on the trans bond strength as widely reported
Correct answer: A. Weakening of the bond trans to a strong trans-influencing ligand (strong sigma donor weakens trans bond)
Explanation: Trans-influence: strong sigma-donor ligands (CO, CN-, H-) weaken and lengthen the metal-ligand bond trans to them by competing for the same metal orbital.
Aqueous solutions of transition metal ions show characteristic colours caused by electrons absorbing visible light to jump between split d-orbitals; the exact colour depends on the metal, its oxidation state, and surrounding ligands.
Concept context
Transition metals (d-block) and lanthanides/actinides (f-block). Known for coloured compounds, variable oxidation states, complex formation, and catalytic properties. Frequently tested in JEE and NEET.