The following reactions are considered redox reactions by the 'loss or gain of oxygen' definition.
PbO(s) + C(s) → Pb(s) + CO(g)
2ZnS(s) + 3O₂(g) → 2ZnO(s) + 2SO₂(g)
a. Explain how they are redox reactions by the 'loss or gain of electrons' definition.
b. Which element in each reaction, apart from oxygen, has been oxidised and which reduced?