Question

How can I identify and draw the optical isomers for all the isomers of `[Co(NH_3 )_2Cl_2 ]^-`

Answer 1

Quite possibly you mean, `[Co(NH_3)_2Cl_4]^-`, i.e. an octahedron, not a tetrahedron.

Explanation:

As written, the cobalt complex would not support optical isomerism. The Co(III) complex, `[Co(NH_3)_2Cl_4]^-`, would support geometric isomerism; it may be cis or trans with respect to the ammine ligands.