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