Which raw material is primarily used to produce ammonia in the Haber process?

The correct option is Nitrogen. This answer is correct because it matches the approved learning objective to explain that ammonia can be used to manufacture ammonium salts. (Chemistry only) in the subtopic Production and uses of NPK fertilisers.

The correct option is Nitrogen. Nitrogen is correct because it directly supports the approved learning objective to explain that ammonia can be used to manufacture ammonium salts. (Chemistry only). This belongs to the subtopic Production and uses of NPK fertilisers within The Haber process and the use of NPK fertilisers, so the explanation must stay tied to that curriculum context. The other options are incorrect because they either do not answer this learning objective, use a vague statement, or move away from Production and uses of NPK fertilisers.