Question

Which of the following compounds show optical isomerism?
(i) $cis-[Co(NH_3)_4Cl_2]^+$
(ii) $trans-[Co(en)_2Cl_2]^+$
(iii) $cis-[Co(en)_2Cl_2]^+$
(iv) $[Co(en)_3]^{3+}$
Choose the correct answer codes given below

• A. i and ii
• B. ii and iii
• C. iii and iv
• D. i, iii and iv
• E. i, ii, iii and iv

Answer 1

Answer: (C)

The compounds, and cis $-\left[ Co ( en )_{2} Cl _{2}\right]^{+}$and $\left[ Co ( en )_{3}\right]^{3+}$ show optical isomerism as they do not possess any element of symmetry. The trans- $\left[ Co ( en )_{2} Cl _{2}\right]^{+}$exists in optically inactive meso form. cis $-\left[ Co \left( NH _{3}\right)_{4} Cl _{2}\right]^{+}$is also optically inactive as it contains plane of symmetry.