Question

The ligand called $\pi$ acid is

• A. $CO$
• B. $N{H}_3$
• C. $C_2{O}_4^{2-}$
• D. ethylene diamine

Answer 1

Answer: (A)

Carbon monoxide is $\pi$ - acid ligand as it characterises both metal to carbon and carbon to metal bonding. The latter is known as $\pi$-acidic character.