Ammonia is a colourless and foul-smelling gas which is composed of hydrogen and nitrogen. It is a simple and stable compound of both these elements and acts as a starting material to produce several nitrogen compounds. It is also amongst the most commonly present hydrides in the atmosphere. The amount of ammonia in the atmosphere is developed mostly because of the bacterial decomposition that is released from the nitrogen-rich elements from plants and animals.
Azane is the IUPAC name of ammonia. The ammonia chemical formula is NH3. Ammonia is present all around us and we are all exposed to a lower concentration of it in our day to day activities. In this article, we will study the properties and preparation of ammonia and nitric acid, the uses of ammonia, ammonium carbonate uses, and the properties of ammonia.
Preparation Of Ammonia
Smaller quantities of ammonia are present in the air and soil because of the decay of the nitrogenous organic matter. To produce ammonia on a small scale, ammonium salts and caustic soda are made to react with each other.
2NH4Cl + Ca(OH)2 → 2NH3 + 2H2O + CaCl2
For a large scale production, Haber’s process is used. The steps that are involved in Haber’s process are:
N2(g) + 3H2(g) ↔ 2NH3 (g)
Nitrogen and hydrogen are used in the form of raw materials for this reaction. The impurities for the gases get removed by a process known as scrubbing.
After this process of scrubbing, the gases are combined and then passed through a compressor. Then the mixture is compressed under a 200 atm pressure.
Then the compressed gases are passed to a converter in which the gases are heated up at a temperature of 450°C and 200 atm pressure. The nitrogen then tends to react with the hydrogen and forms ammonia, however, just about 15% of the total gas is formed.
The mixture of ammonia, nitrogen, and hydrogen is then removed from the converter and cooled wherein it tends to liquefy in the tank and then collected.
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Physical Properties of Ammonia
Chemical Properties of Ammonia
Ammonia is highly soluble in water. The NH3 aqueous solution is a weak base since OH- ions get formed.
NH3 + H2O → N4+ + OH-
Ammonium salts get formed when ammonia reacts with an acid.
ZnSO4 + 2NH4OH (g) → Zn(OH)2 + (NH4)2SO4
Uses of Ammonia
The liquid ammonia includes being used as a refrigerant.
The ammonia gas uses include the manufacturing of urea which is excellent nitrogen fertilizer.
The ammonia solution uses include removing grease since it has cleansing properties.
Friedrich Wilhelm Ostwald in the starting of the 20th century had developed a process wherein ammonia was used for obtaining nitric acid. Due to the development of nitric acid, it had helped the Germans in World War I for making explosives and not importing it from other countries such as Chile. The chemical formula of nitric acid is denoted by HNO3.
Preparation of Nitric Acid
For the small scale preparation, nitric acid is made when concentrated sulphuric acid is heated along with NaNO3 or KNO3.
NaNO3 + H2SO4 → NaHSO4 + HNO3
For the large scale preparations of nitric acid, the Ostwald process is used.
In this process, ammonia undergoes catalytic oxidation through oxygen present in the atmosphere. This happens in the presence of Pt/Rh in the form of a catalyst at 500 K temperature and a pressure of 9 bars.
4NH3 + 5O2 → 4NO(g) + 6H2O
The nitric oxide obtained is then reacted with the oxygen to form NO2.
2NO + O2 → 2NO2(g)
The NO2 formed is then made to dissolve in H2O which forms HNO3.
3NO2 (g) + H2O(l) → 2HNO3(aq) + NO(g)
Properties of HNO3
Nitric acid is colourless in nature.
The boiling point of liquid nitric acid is 84.1°C and it tends to freeze at -41.55 °C and forms a white solid.
It is a strong acid that dissociates and forms nitrate ion and hydronium.
HNO3(aq) +H2O (l) → H3O+(aq) + NO3-(aq)
Nitric acid in its concentrated state tends to act as a strong oxidising state
Cu + 4HNO3 → Cu(NO3)2 + 2NO2 + 2H2O