Final answer:
Out of the given compounds, only compound (c) [Co(H2O)3(CO)3]³⁺ can exhibit fac-mer isomerism.
Step-by-step explanation:
In order to determine which of the given compounds can exhibit fac-mer isomerism, we need to consider the coordination number and geometry of each compound.
Fac-mer isomerism occurs when a complex has three different ligands. The fac isomer has three identical ligands arranged in a face of a meridional plane, while the mer isomer has two identical ligands arranged in one plane and the third different ligand arranged in a different plane.
Out of the given compounds, only compound (c) [Co(H2O)3(CO)3]³⁺ can exhibit fac-mer isomerism. This is because it has three different ligands: three aqua ligands (H2O) and three carbonyl ligands (CO). The three aqua ligands can be arranged in a face of a meridional plane, while the three carbonyl ligands can be arranged in a different plane.