Question

The optically active coordination complex ion among the following is

• A. trans $[Co(en)_{2}Cl_{2}]^{+} $
• B. cis $[Co(en)(NH_{3})_{2}Cl_{2}]^{+} $
• C. $ [Co(NH_{3})_{6}]^{3+} $
• D. $ [Fe(CN_{6})]^{3-} $

Answer 1

Answer: (B)

Usually optical isomerism is exhibited by
$\left[M(a a)_{3}\right]$ or $\left[M(a a)_{2} X_{2}\right]$
or $\left[M(a a) X_{2} 1 / 2\right]$ type complexes.
(Here $M =$ metal atom, $a a=$ bidentate ligand $X$, and $Y =$ unidentate ligand).
Hence, $cis\left[ Co \left(e n\left(N H_{3}\right)_{2} Cl _{2}\right]^{+}\right.$ exhibits optical isomerism. Its optically active forms are as:
Only cis form of tetrahedral complexes of the type $\left[M(a a)_{2 \times 2}\right]^{+}$is optically active.