Question

Which of the following complex will show optical activity?

• A. trans$-[Co(N{H}_3{)}_{4}C{l}_2{]}^{+}$
• B. $[Cr(H_{2}O{)}_6{]}^{3+}$
• C. cis-$[CO(N{H}_3{)}_2(en{)}_2{]}^{3+}$
• D. trans-$[Co(N{H}_3{)}_2(en{)}_2{]}^{3+}$

Answer 1

Answer: (C)

(a) trans$-[CO(N{H}_3{)}_{4}C{l}_2{]}^{+}$ 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-$[Co(N{H}_3{)}_2(ew{)}_2{]}^{3+}$ lacks symmetry elements.