Question

Both geometrical and optical isomerism are exhibited by
A. Dichlorobis ( ethylenediamine) cobalt (III) ion
B. Pentaamminechlorocobalt (III)
C. Triamminotrichlorocobalt (III) ion
D. Tetraamminedichlorocobalt (III) ion

Answer 1

Correct Answer - A
Complex of the type `[M(A A)_(2)X_(2)]` or `[M ( A A)_(2) XY]` exhibit optical activity. `[CoCl_(2)(en)_(2)]^(+)` forms geometrical isomers ( cis and trans form) . It is interesting to note that trans form does not show optical isomeris, i.e., it cannot be resolved into optical isomers. The reason is that the molecule has plane of symmetry . On the other hand , the cis-isomer is unsymmetrical and can be resolved into optical isomers.