Explanation:

Introduction to Ligands:

Ligands are molecules or ions that bind to a central metal ion to form a complex compound. The ligand is a Lewis base as it donates a pair of electrons to the metal center. The number of binding sites on the ligand determines whether it is a monodentate or multidentate ligand. A ligand can be classified as chelating or non-chelating based on its ability to form a cyclic structure with the metal ion.

Monodentate and Multidentate Ligands:

A monodentate ligand has only one binding site, while a multidentate ligand has two or more binding sites. Examples of monodentate ligands are H2O, NH3, Cl-, etc. Examples of multidentate ligands are EDTA, ethylenediamine, diethylenetriamine, etc.

Chelating and Non-Chelating Ligands:

A ligand can be classified as chelating or non-chelating based on its ability to form a cyclic structure with the metal ion. A chelating ligand has two or more binding sites that can simultaneously bind to the metal ion, forming a cyclic structure. This cyclic structure is called a chelate. Examples of chelating ligands are EDTA, ethylenediamine, diethylenetriamine, etc. Non-chelating ligands are those that cannot form a cyclic structure with the metal ion. Examples of non-chelating ligands are H2O, NH3, Cl-, etc.

Option B - A multidentate ligand cannot cause chelation:

This statement is incorrect. A multidentate ligand is capable of forming chelates with the metal ion. Chelation occurs when a multidentate ligand binds to the metal ion through two or more binding sites, forming a cyclic structure. Examples of multidentate ligands that are capable of chelation are EDTA, ethylenediamine, diethylenetriamine, etc. Therefore, option B is not true.

Conclusion:

In conclusion, a ligand can be monodentate or multidentate and can act as a Lewis base. A chelating ligand has two or more binding sites that can simultaneously bind to the metal ion, forming a cyclic structure. A multidentate ligand is capable of forming chelates with the metal ion. Therefore, the correct answer is option B - A multidentate ligand cannot cause chelation.