Sum of oxidation states of bromine in bromic acid and perbromic acid is $..........$

Oxidation number of Nitrogen in $NH_4NO_3$ is

Find out the oxidation number of chlorine in the following compounds and arrange them in increasing order of oxidation number of chlorine.
$NaClO_4, NaClO_3, NaClO, KClO_2, Cl_2O_7, ClO_3, Cl_2O, NaCl, Cl_2, ClO_2$.
Which oxidation state is not present in any of the above compounds?

In polythionic acid,$H_{2}S_{x}O_{6}$ ($x=3$ to $5$),the oxidation state$(s)$ of sulfur is/are:

The oxidation number of $Ba$ in barium peroxide is

Oxidation state of $S$ in $H_2S_2O_8$ is