JEE Chemistry 2023 Question with Solution

Given: We need to identify which complex can show meridional isomerism.

Find: The complex having the possibility of existing as a meridional isomer.

Facial and meridional isomerism arises in octahedral complexes of the $[MA_3B_3]$ type.

The solution states that the $[MA_3B_3]$ type of compound exists as facial and meridional isomer.

Among the given options, [Co(NH$_3$)$_3$(NO$_3$)$_3$] matches the $[MA_3B_3]$ pattern in an octahedral complex.

Therefore, the correct option is D.

Given: Meridional isomerism is associated with geometric isomerism in coordination compounds.

Find: Which given complex can form a mer isomer.

For facial-meridional isomerism, the complex must have three ligands of one type and three ligands of another type arranged octahedrally, that is:

Options with three bidentate en ligands do not represent the required $[MA_3B_3]$ arrangement for fac-mer distinction.

The complex [Co(NH$_3$)$_3$(NO$_3$)$_3$] has three NH$_3$ ligands and three NO$_3$ ligands, so it can exist in fac and mer forms.

Hence, the correct option is D.