Question

Complex compound(s) of which optical activity does not depend upon the orientation of the ligands around metal cation.
(i) $\left[CoC{l}_3\right(N{H}_3{)}_3]$
(ii)$\left[Co\right(en{)}_3]C{l}_3$
(iii) $\left[Co\right(C_2{O}_4{)}_2(N{H}_3{)}_2{]}^{-}$

• A. (i) and (iii)
• B. (i), (ii)
• C. only (ii)
• D. (ii), (iii)

Answer 1

The correct option is C only (ii)

We need to find the complex. When the position of the ligand changed, it does not affect the optical activity of the complex. In other words, the complex does not show geometrical isomerism
(i)$\left[CoC{l}_3\right(N{H}_3{)}_3]$

i.e. show geometrical isomerism depends on orientation of ligand.
(ii)$\left[Co\right(en{)}_3{]}^{3+}i.e.,\left[M\right(AA{)}_3{]}^{+3}$type complex

This compound is optically active due to absence of plane of symmetry also orientation of ligand does not affect optical activity.
(iii)$\left[Co\right(C_2{O}_4{)}_2(N{H}_3{)}_2{]}^{-}$

Geometry of the compound depends on orientation of ligands similarly orientation of ligands in $\left[CrC{l}_2\right(N{H}_3{)}_2\left(en\right){]}^{+}$ affect the optical activity.