Question

Which of the following compounds show optical isomerism?
I. cis$-\left[Co\right(N{H}_3{)}_{4}C{l}_2{]}^{+}$ II. trans$-\left[Co\right(en{)}_{2}C{l}_2{]}^{+}$
III. cis$-\left[Co\right(en{)}_{2}C{l}_2{]}^{+}$ IV. $\left[Co\right(en{)}_3{]}^{3+}$

• A. I and II
• B. II and III
• C. III and IV
• D. I, III and IV

Answer 1

The correct option is C III and IV

The compounds, and $cis-\left[Co\right(en{)}_{2}C{l}_2{]}^{+}$ and $\left[Co\right(en{)}_3{]}^{3+}$ show optical isomerism as they do not possess any element of symmetry. The trans-$\left[Co\right(en{)}_{2}C{l}_2{]}^{+}$ exists in optically inactive meso form.

$cis-\left[Co\right(N{H}_3{)}_{4}C{l}_2{]}^{+}$ is also optically inactive as it contains plane of symmetry.