Explain, in terms of oxidation state, why the following reaction is a redox reaction.

13/08/2020 at 9:04 am (last edited 13/08/2020 at 9:04 am)

PbS (s) + 4H₂O₂ (aq) -> PbSO₄(s) + 4H₂O (l)

PbS has been oxidized to PbSO₄.

The oxidation state of sulfur increased from -2 in PbS to +6 in PbSO₄.

H₂O₂has been reduced to H₂O.

The oxidation state of oxygen decreased from -1 in H₂O₂to -2 in H₂O.

Since oxidation and reduction occurred simultaneously in the reaction, it is a redox reaction.