The right answer is N2(g) + 3H2(g) => 2NH3(g).
Ammonia (NH3) is produced by the synthesis of nitrogen (N2) and hydrogen (H2):
N2 + 3 H2 → 2 NH3
During the first half of the 20th century, the NH3-green was produced without CO2 emission at
from hydroelectricity, water, and atmospheric air.
H2 came from the electrolysis of water, the N2 of atmospheric air.