Ammonia gas is a colourless non-poisonous gas that has pungent smell and strong irritating effect on the eyes, nose, throat and lungs. It is highly soluble in water and a compound of nitrogen and hydrogen. One atom of nitrogen on combining with three atoms of hydrogen forms one molecule of ammonia. This gas can be liquefied by compressing or by cooling at -33°C. At normal temperature and pressure, 700 volumes of ammonia can dissolve in one volume of water. Its solution in water is basic in nature and is known as Ammonium Hydroxide.
There are several methods of making ammonia gas. In the laboratory, this gas is prepared by heating a mixture of ammonium chloride and lime. On a large scale, this gas is manufactured by causing a chemical reaction between hydrogen and nitrogen. This method is called Haber’s Process. In this process one part of nitrogen and three parts of hydrogen are mixed and compressed to 500°C in the presence of iron which acts as a catalyst. Ammonia can also be obtained by distilling coal into coke and coal gas.
Ammonia is very useful to us. It is used in the manufacture of many of its compounds and also for making nitric acid which is used to dissolve many dry cells. This is also used in the dyeing and printing industry.
Ammonium sulphate is an important compound of ammonia. It is made from ammonia and sulphuric acid. It is used as a fertilizer because it provides nitrogen for the soil. Ammonium nitrate is used in fertilizers, explosives and for making nitrous oxide, also called, ‘Laughing Gas’.
The ammonia used as a household cleaner is a strong solution of gas in water. It is also used as cooling agents in refrigerators.
