The two coordination compounds, [Co NH3 4Cl2] and [Co NH3 5Cl], exhibit different types of isomerism due to the different arrangement of ligands around the central metal ion Co . The type of isomerism present in these compounds is called coordination isomerism.1. [Co NH3 4Cl2]: In this compound, the cobalt ion is surrounded by four ammonia NH3 ligands and two chloride Cl ligands. The structure of this compound is octahedral, with the ammonia ligands occupying four vertices of the octahedron and the chloride ligands occupying the remaining two vertices. There are two possible geometric isomers for this compound: cis and trans.Cis isomer: The two chloride ligands are adjacent to each other.Trans isomer: The two chloride ligands are opposite to each other.2. [Co NH3 5Cl]: In this compound, the cobalt ion is surrounded by five ammonia ligands and one chloride ligand. The structure of this compound is also octahedral, with the ammonia ligands occupying five vertices of the octahedron and the chloride ligand occupying the remaining vertex. There is only one possible geometric isomer for this compound.Now, let's discuss optical isomerism. Optical isomers are non-superimposable mirror images of each other, like left and right hands. They have the ability to rotate plane-polarized light in opposite directions.In the case of [Co NH3 4Cl2], neither the cis nor the trans isomer exhibits optical isomerism, as they do not have non-superimposable mirror images.However, in the case of [Co NH3 5Cl], the compound exhibits optical isomerism. The reason is that there is a non-superimposable mirror image of the complex due to the arrangement of the five ammonia ligands and one chloride ligand around the cobalt ion. These two isomers are called enantiomers and can rotate plane-polarized light in opposite directions.In conclusion, the compound [Co NH3 5Cl] exhibits optical isomerism, while [Co NH3 4Cl2] does not.