Question

Which of the following complex will show optical activity?

• A. trans$-[Co(NH_{3})_{4}Cl_{2}]^{+}$
• B. $[Cr(H_{2}O )_{6}]^{3+}$
• C. cis-$[CO(NH_{3})_{2}(en)_{2}]^{3+}$
• D. trans-$[Co(NH_{3})_{2}(en)_{2}]^{3+}$

Answer 1

Answer: (C)

(a) trans$-[CO(NH_{3})_{4}Cl_{2}]^{+}$ has plane of symmetry as well as centre of symmetry. Hence it does not show optical isomerism.
(b) $[Cr(H_{2}O)_{6}]^{3+}$ has plane of symmetry as well as centre of symmetry. Hence it does not show optical isomerism.
(c) cis-$[Co(NH_{3})_{2}(ew)_{2}]^{3+}$ lacks symmetry elements.