QuestionCoordination / optical isomerism
Which one of the following complexes exhibits optical isomerism?
- (a) cis-[PtCl₂(NH₃)₂]
- (b) trans-[PtCl₂(NH₃)₂]
- (c) trans-[Co(en)₂Cl₂]⁺
- (d) [Co(EDTA)]⁻
Answer: (d) [Co(EDTA)]⁻
Square planar Pt complexes have a mirror plane → optically inactive. trans-[Co(en)₂Cl₂]⁺ has a plane of symmetry. [Co(EDTA)]⁻: hexadentate ligand wraps the metal in a chiral arrangement (like M(AA)₃) → optically active → (d).