The oxidation number is the number of electrons an atom gains or loses to form a chemical bond which also helps in deciding whether an element gets reduced or oxidized.
For the compound , the oxidation number of each element present in the compound is represented as;
Oxidation number of
Oxidation number of
Oxidation number of
But the compound is a neutral compound, for which the oxidation number can be calculated by adding the oxidation number of the elements in it.
Thus, the oxidation number of can be calculated as:
=
=
Hence, the oxidation number of is calculated as , as it is a neutral compound.