Question

Both Geometrical & optical Isomerism are shown by:
A. ${{\left[ Co{{(en)}_{2}}C{{l}_{2}} \right]}^{+}}$
B. ${{\left[ Co{{(N{{H}_{3}})}_{5}}C{{l}_{2}} \right]}^{2+}}$
C. ${{\left[ Co{{(N{{H}_{3}})}_{4}}C{{l}_{2}} \right]}^{+}}$
D. ${{\left[ Cr{{(OX)}_{3}} \right]}^{3-}}$

Answer 1

Hint: Geometrical Isomerism: Geometrical isomerism is a type of isomerism that is shown by unsaturated or ring compounds. Here, rotation about the carbon bond is restricted, similarly as in cis and trans configuration.
- Optical Isomerism: Optical isomerism is a type of isomerism in which the arrangement of two isomers in space (3D) are non- superimposable. One compound is the mirror image of the other. This type of isomerism only occurs when the two substances having the same molecular formula but four different groups are bonded with asymmetrical carbon atoms, so that the mirror images are non-superimposable.

Complete Solution :
Both Geometrical & optical isomerism is shown by\[\left[ M\left( A{{A}_{2}} \right){{X}_{2}} \right]\text{ or }\left[ M{{\left( AA \right)}_{2}}XY \right]\] type of complexes. These type of complexes form cis and trans isomerism and show geometrical isomerism as well as show optical isomerism.
- \[{{\left[ Co{{\left[ en \right]}_{2}}C{{l}_{2}} \right]}^{+}}\] shows both Geometrical isomerism as well as optical isomerism. This complex shows Octahedral square planned geometry as well as mirror images which are non-superimposable on each other.
Therefore, the answer is option A- \[{{\left[ Co{{\left[ en \right]}_{2}}C{{l}_{2}} \right]}^{+}}\] Dichloridobis (ethane- 1, 2- diamine) Cobalt (III) ion is the correct option.
So, the correct answer is “Option A”.

Note: Cis and trans isomers show Geometrical isomerism & the prefixes Cis and Trans are Latin words which means "this side of " & "the other side of” respectively. Basically these words are used in stereochemistry of organic chemistry. The orientation of the functional group should be three dimensional. Chiral molecules that are mirror images of one another but are non-super imposable are known as enantiomers.