In Ni(CO)4 the oxidation number of Ni is
The correct option is B
As we know that CO is a neutral ligand, and its oxidation state in metal carbonyl is 0.
Since the overall charge on Ni(CO)4 is 0, the oxidation state of Ni in Ni(CO)4 will be 0.
In a complex sum of oxidation states of all the atoms is always equal to the charge on the complex.
Let the oxidation state of Ni be x.
As the oxidation state of CO is 0,
Hence, the oxidation state of Ni in Ni(CO)4 will be 0.