Which one of the following reactions is an example of decomposition reaction?
1
CH4 (g) + 2O2 (g) → CO2(g) + 2H2O(g)
2
2AgCI(s) \(\rm \xrightarrow{Sunlight} \) 2Ag(s) + CI2(g)
3
CuO + H2 \(\rm \xrightarrow{Heat} \) Cu + H2O
4
Fe(s) + CuSO4 (aq) → FeSO4 (aq) + Cu(s)