The complex which has facial and meridional isomers is (Given : py = pyridine and en = H₂ N - CH₂- CH₂- NH₂ )

Step-by-step solution

Facial and meridional isomerism is exhibited by octahedral complexes of the type [MA₃B₃] . [ Ni(en) ₂( H ₂ O )₂]²⁺ is of the type [M(AA)₂B₂] , which shows cis and trans isomerism. [ Cr(py) ₃( Cl )₃] is of the type [MA₃B₃] , which shows facial (fac) and meridional (mer) isomerism. [ Cr(H ₂ O )₆]³⁺ is of the type [MA₆] , which does not show geometrical isomerism. [ Co(NH ₃)₄( H ₂ O )₂]³⁺ is of the type [MA₄B₂] , which shows cis and trans isomerism. Answer: [ Cr(py) ₃( Cl )₃]