2 NH4NO3 (aq) → 4 H2O (l) + O2 (g) + 2 N2 (g)
This is an oxidation-reduction (redox) reaction:
2 N-III - 6 e- → 2 N0 (oxidation)
2 NV + 10 e- → 2 N0 (reduction)
2 O-II - 4 e- → 2 O0 (oxidation)
NH4NO3 is a reducing agent, NH4NO3 is an oxidizing agent, NH4NO3 is a reducing agent.
This is a gas evolution reaction, O2 and N2 is the formed gas.