(i) Haber's process is an exothermic reaction. So, low temperature will help the formation of ammonia. However, low temperature impedes the reaction rate. A compromise is achieved at 400-500oC and once this temperature is reached, the source of heat is removed.
(ii) Ammonium nitrate is explosive and decomposes to yield nitrous oxide and water vapour. As a result, it is not used in the laboratory preparation of ammonia.
(iii) Ca(OH)2 is not as deliquescent as NaOH. Moreover, it is cheap and easily available.
(iv) Liquid NH3 does not contain hydroxyl groups and as a result, it will not show any action on litmus paper. However, liquor NH3, also called NH4OH, is alkaline and turns red litmus blue.
(v) Ammonia is highly soluble in water. To prevent loss of ammonia by dissolution in water, nitrogen and hydrogen used in the Haber's process must be completely dry.
(vi) Finely divided molybdenum is used as a promoter in the Haber's process to increase the efficiency of the catalyst, iron.
(vii) Aqueous ammonia contains OH- ions that help in the conduction of electricity.
(viii) Ammonia is highly soluble in water. As a result, it cannot be collected over water.
(ix) Ammonia is formed by the decomposition of urine, which is present in sewage water.
(x) Ammonia solution contains ammonium hydroxide that gives different coloured precipitates on reaction with different metal ions.