Which of the following does not show optical isomerism? (en= ethylenediamine)

Options

A. `[Co(NH_(3)_(3)Cl_(3)]`
B. `[Co(en)_(3)Cl_(3)]`
C. `[Co(en)_(2)Cl_(2)Cl]`
D. `[Co(en)(NH_(3))_(2)Cl_(2))]Cl`

Answer

A

Explanation

Optical isomerism is very common in octahedral complexexes of general formulae,`[M("AA")_(a_(2))b_(2)c_(2)]^(n+),[Mabcded],[M("AA")_(3)]^(n+),[M("AA")_(2)a_(2)]^(n+)`
`[M("AA")a_(2)b_(2)ab]^(n+)`and `[M(AB)_(3)]^(n+)s`.Where AA is symmertrical bidentate ligand and AB is unsymmetrical complex of the type` Ma_(4)b_(2)` and `Ma_(3)b_(3)`exhibit geometrical isomerism.