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Given below are two statements: one is labelled as “Assertion A” and the other is labelled as “Reason R” Assertion A : In the complex Ni(CO)4 and Fe(CO)5, the metals have zero oxidation state. Reason R : Low oxidation states are found when a complex has ligands capable of π-donor character in addition to the σ-bonding. In the light of the above statements, choose the most appropriate answer from the options given below

1. A is correct but R is not correct
2. A is not correct but R is correct
3. Both A and R are correct but R is NOT the correct explanation of A
4. Both A and R are correct and R is the correct explanation of A

Correct answer: A is correct but R is not correct

Solution

Assertion A is correct because both Ni in Ni(CO)4 and Fe in Fe(CO)5 are indeed in the zero oxidation state. However, Reason R is not correct in this context because while π-donor ligands can stabilize low oxidation states, the presence of CO, a strong field ligand, does not specifically explain the zero oxidation state of the metals in these complexes.

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