NTA Abhyas JEE Main2020ChemistryCoordination CompoundsPractice
Which one of the following complexes will most likely absorb visible light? (Atomic numbers: Sc = 21, Ti = 22, V = 23, Zn = 30)
Options
- A[Sc(H 2 O) 6 ] 3+
- B[V(NH 3 ) 6 ] 3+
- C[Ti(NH 3 ) 6 ] 4+
- D[Zn(NH 3 ) 6 ] 2+
Correct answer
B. [V(NH 3 ) 6 ] 3+
Step-by-step solution
The two electrons present in t 2g orbitals can show d-d transitions between t 2g and e g orbitals by absorbing visible light as CFSE is not very high due to weak NH 3 ligand field in an octahedral geometry 2 1 Sc 3 + → 3 d ∘ 2 2 Ti 4 + → 3 d ∘ 3 0 Zn 2 + → 3 d 1 0 Configurations and d-d transitions leading to colouration etc, are not feasible.