Which one is an incorrect combination?
| List-I (Ligands) | List-II (Characteristics) |
|------------------------|----------------------------|
| (P) Thiosulphate ion | (1) Bidentate ligand |
| (Q) ortho-phenanthroline | (2) Chelating ligand |
| (R) oxalate ion | (3) Contains a chiral centre|
| (S) pn | (4) Monodentate ligand |
| | (5) Ambidentate ligand |
| | (6) Flexidentate ligand |
Answer (1)
To determine the incorrect combination, we need to understand the terms associated with ligands and their characteristics.
Here's a step-by-step breakdown of each option:
Thiosulphate ion (P) : This ligand has the characteristic formula S 2 O 3 2 − . It is known to be a bidentate ligand , meaning it can attach to the central atom in a coordination complex at two different binding sites.
Ortho-phenanthroline (Q) : This is a heterocyclic organic compound that serves as a chelating ligand because it can bind with a metal ion in multiple locations, typically forming a stable complex.
Oxalate ion (R) : The oxalate ion C 2 O 4 2 − is a well-known bidentate chelating ligand as it has two donor atoms which form bonds with a metal.
pn (S) : This is probably referring to 1,2-diaminoethane (also known as ethylenediamine), a bidentate ligand . It does not contain a chiral center unless otherwise specified by substitutions.
Now, let's analyze the given combinations:
Thiosulphate ion (P) matches with (1) Bidentate ligand.
Ortho-phenanthroline (Q) aligns with (2) Chelating ligand.
Oxalate ion (R) should match (1) Bidentate ligand, not with (3) Contains a chiral centre, as oxalate does not have a chiral center.
pn (S) can be confusing if not specified correctly as it might relate to being a bidentate ligand and not have a chiral center.
From the options, the incorrect combination stems from oxalate ion (R) being linked to (3) "Contains a chiral centre," since oxalate is neither monodentate nor does it contain a chiral center. Therefore, the incorrect combination is ( R ) − ( 3 ) .
This question focuses on understanding the chemical nature of ligands and their role in complex formation in coordination chemistry.
