Question

Answer the following:
Co\(^{2+}\) is easily oxidized to Co\(^{3+}\) in the presence of a strong ligand (At. No. of Co = 27).

Hint:

Strong field ligands can stabilize high oxidation states, like Co\(^{3+}\), by creating a strong ligand field.

Answer 1

Cobalt in the +2 oxidation state (Co\(^{2+}\)) has a relatively low stability due to the presence of a higher number of electrons in its d-orbitals, leading to higher repulsion between them. When a strong ligand, such as ammonia (NH₃) or cyanide (CN⁻), is present, it can create a strong ligand field that stabilizes Co\(^{3+}\) by lowering the energy of the d-orbitals. As a result, Co\(^{2+}\) is easily oxidized to Co\(^{3+}\), which is more stable due to the lower electron-electron repulsion in the 3d⁶ configuration.