Which of the following complexes cannot have geometric isomers?
i) [PtCl₂(NH₃)₂]
ii) K₄[Fe(CN)₄(OH)₂]
iii) [Ag(NH₃)₂]Cl
iv) [Ni(H₂O)₂(NH₃)₂]Br₂

• A. i, ii, and iv
• B. ii and iv
• C. iii only
• D. i and iii
• E. iv only

Answer: (C)

Verified step by step guidance

1. Identify the coordination number and geometry of each complex. For example, [PtCl2(NH3)2] has a coordination number of 4 and typically forms a square planar geometry.
2. Determine if the complex can exhibit geometric isomerism. Geometric isomerism occurs in square planar and octahedral complexes, but not in linear or tetrahedral complexes.
3. Analyze [PtCl2(NH3)2]: As a square planar complex, it can have cis and trans isomers, so it can exhibit geometric isomerism.
4. Examine [Ag(NH3)2]Cl: This complex has a linear geometry with a coordination number of 2, which does not allow for geometric isomerism.
5. Review the other complexes: K4[Fe(CN)4(OH)2] and [Ni(H2O)2(NH3)2]Br2 both have octahedral geometries, which can exhibit geometric isomerism. Therefore, the complex that cannot have geometric isomers is [Ag(NH3)2]Cl.