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

Answer 1

Answer: (C)

iii and iv

Answer 2

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.