Explanation:
Cr(CO)6 is a coordination compound where Cr is bonded with 6 CO molecules.

Oxidation State:
Oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were completely ionic. The oxidation state of an atom in a molecule refers to the degree of oxidation of that atom.

Cr(CO)6:
In Cr(CO)6, each CO molecule is bonded with Cr through a dative covalent bond. Each CO molecule donates a pair of electrons to the Cr atom, which forms a coordinate covalent bond. Since there are six CO molecules, the coordination number of Cr is six.

Calculation:
To find the oxidation state of Cr in Cr(CO)6, we assume that all the CO molecules are neutral and the overall charge of the complex is zero.

The oxidation state of carbon in CO is -2, as oxygen is more electronegative than carbon, and electrons are shared unequally in the bond.

Therefore, the total charge contributed by six CO molecules is (-2) x 6 = -12.

Since the overall charge of the complex is zero, the oxidation state of Cr can be calculated as follows:

Oxidation state of Cr + Total charge contributed by six CO molecules = Overall charge of the complex

Oxidation state of Cr - 12 = 0

Oxidation state of Cr = +12

However, this value is not a possible oxidation state for Cr. Therefore, we assume that the oxidation state of Cr is zero, as it is the only possible oxidation state for Cr in this complex.

Conclusion:
The oxidation state of Cr in Cr(CO)6 is 0.

Look here CO is carbon monoxide nd it is a neutral legend means has 0 charge so oxidation state of Cr is 0