PbO2 (s) + 4 HCl (aq) → PbCl2 (s) + Cl2 (g) + 2 H2O (l)
This is an oxidation-reduction (redox) reaction:
PbIV + 2 e- → PbII
(reduction)
2 Cl-I - 2 e- → 2 Cl0
(oxidation)
PbO2 is an oxidizing agent, HCl is a reducing agent.
