The oxidation state of $P$ in $KH_2PO_2$ is .........

The oxidation number of $N$ in $NH_4Cl$ is

In the reaction,$MnO_{4(aq)}^{-} + Br_{(aq)}^{-} \rightarrow MnO_{2(s)} + BrO_{3(aq)}^{-}$,the correct change in oxidation number of the species involved is

What is the oxidation number of sulfur in $H_2S_2O_8$?

What is the oxidation number of chlorine in $ClO_3^-$?

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