Sulphur in $+3$ oxidation state is present in

One mole of $N_2H_4$ loses $10 \ moles$ of electrons to form a new compound $Z$. Assuming that all the nitrogen atoms appear in the new compound, what is the oxidation state of nitrogen in $Z$? (There is no change in the oxidation state of hydrogen.)

In which compound is the oxidation state of nitrogen $-1$?

$A$ compound contains atoms $X$,$Y$,and $Z$. The oxidation number of $X$ is $+2$,$Y$ is $+5$ and $Z$ is $-2$. Therefore,a possible formula of the compound is

What is the change in the oxidation state of $Mn$ in the reaction of $MnO_4^{-}$ with $H_2O_2$ in acidic medium?

What are the oxidation states of $S$ in peroxodisulphuric acid and sodium tetrathionate?