What are the oxidation numbers of hydrogen in $KH$,$MgH_2$,and $NaH$ respectively?

When $KMnO_4$ acts as an oxidising agent and ultimately forms $[MnO_4]^{2-}$,$MnO_2$,$Mn_2O_3$,and $Mn^{2+}$,the number of electrons transferred in each case respectively is:

Suggest a list of substances where carbon can exhibit oxidation states from $-4$ to $+4$ and nitrogen from $-3$ to $+5$.

The oxidation numbers of the two $Cl$ atoms in bleaching powder,$CaOCl_2$,are

The oxidation state of chlorine in $KClO_4$ is

Oxidation number of $Mn$ in $K_2MnO_4$ and in $KMnO_4$ are respectively