AP EAPCET 19-Aug-2021 Shift 1 Paper

Coordination number is defined as number of coordinate bonds of central metal atom with the ligand. Here, en is bidentate ligand and Cl− is monodentate ligand.
In the given complex, Co binds with two a bidentate ligand en (2×2=4) and two monodentate ligand (2×1=2).
∴ Its coordination number is, 4+2=6.