Which of the following has an optical isomer?
(en=ethylenediamine) ?

Options

A. `[Zn(en)_(2)]^(2+)`
B. `[Zn(en)(NH_(3))_(2)]^(2+)`
C. `Co(en)_(3)]^(3+)`
D. `[CO(H_(2)O)_(4)(en)]^(3)`

Answer

C

Explanation

`[Ma_(2)b_(2)c_(2)]^(n pm),[Mabcdef]^(n pm)`,
`[M(A A)_(3)]^(n pm),[M(A A)_(2)a_(2)]^(n pm),`
`[M(A A)_(2)ab]^(n pm) and [M(AB)_(3)]^(n pm)`.
Thus, among the given options, only `[Co(en)_(3)]^(3+)` shows optical isomerism.