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

Options

A. (a) `[Zn(en)(NH_3)_2]^(2+)`
B. (b) `[Co(en)_3]^(3+)`
C. (c) `[Co(H_2O)_4(en)]^(3+)`
D. (d) `[Zn(en)_2]^(2+)`

Answer

B

Explanation

Complex `[Co(en)_3]^(3+)` has no plane of symmetry and centre of symmetry. That's why, it is optically active.