Describe the role of the iron catalyst in the Haber process.

The iron catalyst in the Haber process speeds up the reaction between nitrogen and hydrogen to form ammonia without being consumed in the reaction. This allows the process to occur at a lower temperature and pressure than would otherwise be necessary.

A strong answer should directly address the approved learning objective to describe the Haber process as the industrial manufacture of ammonia. (Chemistry only). This question belongs to The Haber process within The Haber process and the use of NPK fertilisers, so the response should use that exact curriculum context rather than a generic statement. The answer is correct when it names the key idea, explains the link to chemistry only, and keeps the wording specific to AQA GCSE revision.