The existence of two different coloured complexes with the composition of [ Co ( NH ₃ )₄ Cl ₂ ]⁺ is due to

Step-by-step solution

Key Idea Complexes of [ MA ₄ ~B ₂ ] type exhibit geometrical isomerism. The complex [ Co ( NH ₃ )₄ Cl ₂ ]⁺ is a [ MA ₄ ~B ₂ ] type complex and thus, fulfills the conditions that are necessary to exhibit geometrical isomerism. Hence, it has two geometrical isomers of different colours as : The structure of the geometrical isomers is as For linkage isomerism, presence of ambidentate ligand is necessary. For coordination isomerism, both the cation and anion of the complex must be complex ions. For ionisation isomerism