In Haber process, N₂ reacts with H₂ and produces NH₃. The balanced reaction for the Haber process is
N₂(g) + 3H₂(g) → 2NH₃(g)
The stoichiometric ratio between N₂ and H₂ is 1 : 3
This means, reacted moles of N₂ = reacted moles of H₂ / 3
Hence, 3 moles of H₂ react with 1 mole of N₂ to form 2 moles of NH₃.