Which of the following is a Chelating ligand?

The chelating ligand among the options is (3) oxalate.

A chelating ligand is a ligand that can donate more than one pair of electrons to a metal atom. This results in the formation of a chelate complex, which is a complex in which the ligand forms a ring around the metal atom.

Thiocyanate, cyanide, and ammonia are all monodentate ligands, which means that they can only donate one pair of electrons to a metal atom. Therefore, they cannot form chelate complexes.

Oxalate is a bidentate ligand, which means that it can donate two pairs of electrons to a metal atom. This allows it to form a chelate complex with the metal atom.