Question

$CO$ is a stronger ligand than $C{l}^{-}$ because

• A. $CO$ is a neutral molecule
• B. $CO$ has $\pi$-bonds.
• C. $CO$ is poisonous.
• D. $CO$ is more reactive.

Answer 1

Answer: (B)

CO is a strong ligand due to the presence of $\pi$ -bonds, available for donating $\pi$ -electrons to the metal-ion/atom. While, $C{l}^{-}$ has pair of electrons but are less available for donation (due to more delocalised nature of $\pi$ -electrons).