An aqueous solution of ammonium nitrite, NH,NO2, decomposes when heated to give off nitrogen, N2. \mathrm{NH}_{4} \mathrm{NO}_{2(\mathrm{~s})} \rightarrow \mathrm{N}_{2 \mathrm{(g})}+2 \mathrm{H}_{2} \mathrm{O}_{(1)}