JEE MainChemistryCoordination Compounds
An unknown octahedral complex of Co(III) containing ammonia and chloride ligands is found to be diamagnetic. When treated with excess AgNO ₃ solution, it yields 1 mole of AgCl precipitate per mole of the complex. Which statement is correct regarding the isomerism of this complex?
Options
- AIt exhibits both geometrical and optical isomerism.
- BIt exhibits optical isomerism but not geometrical isomerism.
- CIt exhibits geometrical isomerism but not optical isomerism.
- DIt exhibits neither geometrical nor optical isomerism.
Correct answer
C. It exhibits geometrical isomerism but not optical isomerism.
Step-by-step solution
The complex yields 1 mole of AgCl precipitate per mole of the complex, indicating that there is exactly one Cl ⁻ ion present in the ionization sphere. Since the central metal is Co(III) and it forms an octahedral complex (coordination number = 6), the total number of chloride ions must be 3 to balance the +3 charge of cobalt (as ammonia is a neutral ligand). With one Cl ⁻ outside the coordination sphere, two Cl ⁻ ions must be inside. To satisfy the coordination number of 6, four NH ₃ molecules must also be inside t