Question

Which one of the following has an optical isomer?
(a) [Zn(en) (NH₃)₂]²⁺ (b) [Co(en)₃]³⁺
(c) [Co(H₂O)₄(en)]³⁺ (d) [Zn(en)₂]²⁺
(en = ethylenediamine)

Answer 1

b)[Co(en)3]3+  will have optical isomer.

Explanation:

The correct answer is [Co(en)3]3+

 As [Co(en)3]3+ has no plane of  symmetry it is optically ACTIVE.

Square planar complexes of Zn2+ cannot show optical isomerism. Hence, it is ruled out. It will have two planes of symmetry. Thus, it is optically inactive.

 Option a and c also has planes of symmetry thus optically inactive.