Q38 / 180 · COMEDK 2024 (Morning Shift) · Chemistry
Choose the incorrect statement from the following.
- AA tetrahedral complex of the type $[\mathrm{Ma}_2 \mathrm{b}_2]$ does not show geometrical isomerism
- BIn a coordination entity of the type $[\mathrm{Ma} 2(\mathrm{bb})_2]^{2+}$ only the cis-isomer is optically active
- Correct answerCCoordination entities of the type $[\mathrm{Ma}_3 \mathrm{b}_3]$ do not exhibit geometrical isomerism
- DSquare planar complex  of the type [Mabcd] has 3 possible geometrical isomers
Solution
In a tetrahedral complex of the type $[Ma_2b_2]$, all positions are equivalent relative to each other, meaning there is no distinction between cis and trans positions. Thus, it does not show geometrical isomerism. This statement is correct.
For a coordination entity of the type $[Ma_2(bb)_2]^{2+}$, where $(bb)$ is a symmetrical bidentate ligand, the cis-isomer lacks a plane of symmetry and is optically active, while the trans-isomer possesses a plane of symmetry and is optically inactive. This statement is correct.
Coordination entities of the type $[Ma_3b_3]$ exhibit facial (fac) and meridional (mer) geometrical isomers. Therefore, the statement that they do not exhibit geometrical isomerism is incorrect.
A square planar complex of the type $[Mabcd]$ has three possible geometrical isomers, which are obtained by fixing one ligand and arranging the others in different positions relative to it. This statement is correct.
Answer: Coordination entities of the type $[\mathrm{Ma}_3 \mathrm{b}_3]$ do not exhibit geometrical isomerism
For a coordination entity of the type $[Ma_2(bb)_2]^{2+}$, where $(bb)$ is a symmetrical bidentate ligand, the cis-isomer lacks a plane of symmetry and is optically active, while the trans-isomer possesses a plane of symmetry and is optically inactive. This statement is correct.
Coordination entities of the type $[Ma_3b_3]$ exhibit facial (fac) and meridional (mer) geometrical isomers. Therefore, the statement that they do not exhibit geometrical isomerism is incorrect.
A square planar complex of the type $[Mabcd]$ has three possible geometrical isomers, which are obtained by fixing one ligand and arranging the others in different positions relative to it. This statement is correct.
Answer: Coordination entities of the type $[\mathrm{Ma}_3 \mathrm{b}_3]$ do not exhibit geometrical isomerism
Hence, the correct answer is option: 'C'.