Question

In the following reaction between lead sulphide and hydrogen peroxide:

\[\ce{PbS_{(s)} + 4H2O2_{(aq)} -> PbSO4_{(s)} + 4H2O_{(l)}}\]

1. Which substance is reduced?
2. Which substance is oxidised?

Answer 1

1. Reduction is the loss of oxygen. Hydrogen peroxide (H₂O₂) loses oxygen atoms as it converts into water (H₂O). Therefore, Hydrogen peroxide (H₂O₂) is reduced.
2. Oxidation is the gain of oxygen. Lead sulphide (PbS) gains four oxygen atoms to form lead sulphate (PbSO₄). Therefore, Lead sulphide (PbS) is oxidised.