Which gas is commonly used in the Haber process for ammonia production?

In the Haber process, nitrogen is indeed a key reactant used for the synthesis of ammonia. The process combines nitrogen, typically sourced from atmospheric air (which is about 78% nitrogen), with hydrogen under high pressure and temperature in the presence of a catalyst. The overall reaction is:

N₂(g) + 3H₂(g) ⇌ 2NH₃(g).

This reaction is highly significant in industrial chemistry as it provides a method for producing ammonia, which is essential for fertilizers and various chemical products. The use of nitrogen is crucial because it reacts with hydrogen to form ammonia, whereas the other options listed (oxygen and carbon dioxide) do not participate in this particular reaction for ammonia production. Hydrogen is also a reactant in this process but is not the answer you indicated. Understanding the role of nitrogen highlights its importance in the development of agricultural technologies and food production.