Question

Assertion CO and CN are referred as $\pi$ acid ligands.
Reason In CO and CN vacant $\pi$ type orbitals are present.

• A. Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
• B. Both Assertion and Reason are true and Reason is not the correct explanation of Assertion.
• C. Assertion is true but Reason is false.
• D. Both Assertion and Reason are false.

Answer 1

Answer: (A)

The ligands having vacant $\pi$-type orbitais have a tendency to receive back donated $\pi$ electrons, thus these are called $\pi$-acid ligands or $\pi$ acceptor ligands, e.g., CO and NO have Ione pair as well as $\pi$ or ${\pi }^{\ast }$ orbitais which take part in the formation of $\pi$-bond with central metaI atom as observed in case of carbonyls.