The oxidation state of sulphur in $H_2S_2O_7$ is

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

Oxidation state of oxygen in $F_2O$ is

What is the change in oxidation number of selenium in the following redox reaction?
$SeO_{3(aq)}^{2-} + Cl_{2(g)} + 2OH^- \longrightarrow SeO_{4(aq)}^{2-} + 2Cl_{(aq)}^- + H_2O$

What is the oxidation state of oxygen in $OF_2$?

What is the oxidation state of $Fe$ in $Fe_{0.94}O$?