Question

Which one of the following complexes shows optical isomerism? (en=ethylendiamine)

• A. $trans \, \left[C o \left(e n\right)_{2} \, C l_{2}\right] \, Cl$
• B. $\left[C o \left(N H_{3}\right)_{4 \, C l_{2}}\right] \, Cl_{ \, }$
• C. $\left[C o \, \left(N H_{3}\right)_{3} \, C l_{3}\right]$
• D. $cis \, \left[C o \left(e n\right)_{2} \, C l_{2}\right]Cl$

Answer 1

Answer: (D)

$\left[\right.Co\left(\right. \left(NH\right)_{3} \left.\right)_{3}\left(Cl\right)_{3}\left]\right.$ shows two geometrical isomers and both can't show optical isomerism due to presence of plane of symmetry.

$cis \, \left[C o \left(e n\right)_{2} C l_{2}\right]Cl$ shows optical isomerism


$trans \, \, \left[Co \left(e n\right)_{2} C l_{2}\right]Cl$ forms identical mirror image due to presence of plane of symmetry.


$\left[\right.Co\left(\right. \left(NH\right)_{3} \left.\right)_{4}\left(Cl\right)_{2}\left]\right.$ shows geometrical isomerism.