Oxidation number of oxygen in potassium superoxide $(KO_2)$ is

An acidic solution of sodium thiosulfate is unstable because in thiosulfate,the two sulfur atoms have different oxidation states of:

What is the oxidation number of $Fe$ in $Fe_3O_4$?

In the following reaction,assign the oxidation state of the underlined atom for the product of complete hydrolysis at $R.T.$:
$H\underline{N}O_4 + H_2O \longrightarrow HNO_3 + H_2O_2$

What is the oxidation state of phosphorus in the phosphate ion $(PO_4^{3-})$?

The oxidation number of nitrogen atoms in $NH_4NO_3$ are