<span>The overall reaction is as follows:
H2O2 + 2ClO2 => 2ClO2- + O2 + 2H+
Half cell reactions:
</span><span>ClO2 + e- => ClO2-
</span><span>H2O2 => O2 + 2H+ + 2e- </span>
The oxidation state of a free element (uncombined element) is zero. For a simple (monoatomic) ion, the oxidation state is equal to the net charge on the ion. For example, Cl– has an oxidation state of -1. When present in most compounds, hydrogen has an oxidation state of +1 and oxygen an oxidation state of −2.
He put iron with sulfur and oxygen and it had a few more errors and iron is a metal the other two are nonmetals