Question

Which of the following compounds shows optical
isomerism?
(a) [Co(CN)₆ ]³⁻ (b) [Cr(C₂O₄ )₃ ]³⁻
(c) [ZnCl₄ ]²⁻ (d) [Cu(NH₃ )₄ ]²⁺

Answer 1

b)[[Cr(C₂O₄ )₃ ]³⁻ will have optical isomer.

Explanation:

The correct answer is [Cr(C₂O₄ )₃ ]³⁻

 As [Cr(C₂O₄ )₃ ]³⁻ has no plane of  symmetry it is optically ACTIVE.

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

 Option a and cand dalso has planes of symmetry thus optically inactive.