Identify a redox reaction.
2Pb(NO3)2(s) → Heat 2PbO(s) + 4NO2(g) + O2(g)
CaCO3(s) → Heat CaO(s) + CO2(g)
MnO2 + 4HCl → MnCl2 + 2H2O + Cl2
Pb(s) + CuCl2(aq) → PbCl2(aq) + Cu(s)
C. MnO2 + 4HCl → MnCl2 + 2H2O + Cl2