Which of the following is a thermite reaction?
1
Fe (s) + CuSO4 (aq) → FeSO4 (aq) + Cu (s)
2
3 MnO2 (s) + 4 Al (s) → 3 Mn (l) + 2 Al2O3 (s) + heat
3
Fe2O3 (s) + 2 Al (s) → 2 Fe (l) + Al2O3 (s) + heat
4
Cu2O + Cu2S \(\underrightarrow{Heat} \) 6 Cu (s) + SO2 (g)