Chemical Properties of Hydrogen
Combustion
Hydrogen is combustible and burns in air with pale blue flame.
2H2 + O2 → 2H2O
Reducing Property
Hydrogen reduces heated metal oxides to metals.
ZnO + H2 → Zn + H2O
CuO + H2 → Cu + H2O
Reaction with Non-Metals
Hydrogen combines with nitrogen, carbon, oxygen and chlorine under appropriate conditions to form ammonia, methane, water and hydrogen chloride, respectively.
3H2 + N2 → 2NH3
2H2 + C → CH4
2H2 + O2 → 2H2O
H2 + Cl2 → 2HCl
Reaction with Metals
Hydrogen reacts with highly electropositive metals to from the corresponding hydrides.
2Na + H2 → 2NaH
2Li + H2 → 2LiH