QJEEM23Ch03a8: JEE Main 2023 Chemistry - Class 12 JEEM23Ch03a8 Solution: The set which does not have ambidentate ligand(s) is :

Option A :

- $${\mathrm{C}}_2{\mathrm{O}}_4{}^{2-}$$ (Oxalate) is a bidentate ligand. It always binds through its two oxygen atoms.

- $${\mathrm{NO}}_2{}^{-}$$ (Nitrite) is an ambidentate ligand. It can coordinate either through nitrogen or oxygen.

- $${\mathrm{NCS}}^{-}$$ (Thiocyanate) can also bind through either nitrogen or sulfur, making it an ambidentate ligand.

Option B :

- $${\mathrm{C}}_2{\mathrm{O}}_4{}^{2-}$$ (Oxalate) as mentioned earlier, is a bidentate ligand.

- Ethylene diamine (en) is also a bidentate ligand, as it always binds through its two nitrogen atoms.

- $${\mathrm{H}}_2\mathrm{O}$$ (Water) is a monodentate ligand, binding only through one oxygen atom.

Option C :

- $${\mathrm{NO}}_2^{-}$$ as mentioned, is an ambidentate ligand.

- $${\mathrm{C}}_2{\mathrm{O}}_4{}^{2-}$$ as mentioned, is a bidentate ligand.

- $${\mathrm{EDTA}}^{4-}$$ is a hexadentate ligand. It always binds through six donor atoms and is not ambidentate.

Option D :

- $${\mathrm{EDTA}}^{4-}$$ as mentioned, is a hexadentate ligand.

- $${\mathrm{NCS}}^{-}$$ as mentioned, is an ambidentate ligand.

- $${\mathrm{C}}_2{\mathrm{O}}_4{}^{2-}$$ as mentioned, is a bidentate ligand.

From the above analysis, it's clear that Option B is the one that does not contain any ambidentate ligands. So, the correct answer is Option B.