2 NH4OH (l) + 4 Fe2(SO4)3 (s) → N2O (g) + 8 FeSO4 (aq) + 4 H2SO4 (aq) + H2O (l)
This is an oxidation-reduction (redox) reaction:
2 N-III - 8 e- → 2 NI (oxidation)
8 FeIII + 8 e- → 8 FeII (reduction)
NH4OH is a reducing agent, Fe2(SO4)3 is an oxidizing agent.