What is ammonium nitrate(NH4NO3)?
Ammonium nitrate is a chemical and also an inorganic compound with molecular formula NH4NO3. It is an important N-containing fertilizer and predominantly used in agriculture.
It is white or grey crystalline as well as hygroscopic solid, although it does not form hydrates with water.
The density of ammonium nitrate is 1.7 gm / cc. It has a trigonal crystal structure. The melting point of ammonium nitrate is 442.6K and its boiling point is 483K.
Ammonium nitrate is highly soluble in water due its ionic nature. The dissolution of ammonium nitrate in water is endothermic process.
The solubility of NH4NO3 in water 1.5 gm /cc at 293K and it increases to 10.2 gm/cc at 373K temperature.
Ammonium nitrate is an explosive substance. For this reason it is used as a component of explosives mixtures which is used in mining, quarrying, and civil construction.
It is also the main ingredient in ANFO (ammonium nitrate / fuel oil). Ammonium nitrate is used in most explosive preparations.
Thousands of people have died in ammonium nitrate explosions in the past. As a result, many countries are stopping its use as an explosive.
Ammonium nitrate formula
From mass diffraction analysis, it has been proved that the chemical formula of ammonium nitrate is NH4NO3. It has trigonal crystal structure.
Both covalent and electrolytic bonds are present in the ammonium nitrate molecule.
Chemical Properties
Ammonium nitrate is used as an explosive that is as a component of explosive.
But ammonium nitrate itself is not explosive. It must be mixed with a primary explosive such as an azide to form an explosive mixture.
When ammonium nitrate is heated, it decomposes to produce nitrous oxide and water.
NH4NO3 ⟶ N2O + 2H2O
When NH4NO3 reacts with hydroxides of alkali metals it produces metallic nitrates and ammonia.
What is ammonium nitrate made of?
The industrial production of ammonium nitrate is by the reaction of ammonia gaswith concentrated nitric acid.
The reaction is an example of an acid-base reaction. The reaction is violent as it is exothermic in nature.
HNO3 + NH3 → NH4NO3 + heat
Ammonium nitrate may also be prepared by the reaction of tin metal with cold and dilute nitric acid.
5 Sn + 20 HNO3 ⟶ 4Sn (NO3)2 + NH4NO3 + 3H2O
Another production method is a variant of the nitro-phosphate process.
Ca (NO3)2 + 2 NH3 + CO2 + H2O → 2 NH4NO3 + CaCO3
The products, calcium carbonate and ammonium nitrate may be separately purified.
Ammonium nitrate can also be made via metathesis reactions. The reactions are shown below.
(NH4)2SO4 + Ba (NO3)2 → 2 NH4NO3 + BaSO4
NH4Cl + AgNO3 → NH4NO3 + AgCl
What is ammonium nitrate used for?
There are two basic use of ammonium nitrate. These two are, use of ammonium nitrate as fertilizer and as explosive.
Fertilizer
Ammonium nitrate is an important nitrogenous fertilizer which contain of 35% nitrogen. It is less concentrated than urea.
The advantage of ammonium nitrate over urea is that it is more stable. This is why ammonium nitrate does not lose nitrogen in the atmosphere quickly.
Explosives
Ammonium nitrate is a major component of certain explosives. Some examples of explosives with ammonium nitrate are given below.
Astrolite, amatol (ammonium nitrate and TNT), ammonal (ammonium nitrate and aluminum powder), ANFO (94% ammonium nitrate and 6%fuel oil), DBX, and minol etc are notable.
It is also used in the mining and construction industry as a material of explosives.
Terrorism
Ammonium nitrate-based explosives were used in the 2011 Delhi bombings and in the 2013 Hyderabad blasts.
Terrorists have used ammonium nitrate based explosives for explosion in many countries around the world. For this reason, many countries are stopping its use as an explosive.
Niche uses
The dissolution of ammonium nitrate in water is highly endothermic. For this reason, it is used in some instant cold packs.
A solution of ammonium nitrate with nitric acid may also be used in spacecraft as a more energetic alternative to the common monopropellant hydrazine.
Ammonium nitrate health hazards
Although explosive, ammonium nitrate is generally not dangerous to health. It is commonly used in fertilizer products.
What is ammonium nitrate fertilizer?
Ammonium nitrate is a nitrogenous inorganic compound. Ammonium nitrate is a salt of ammonia and nitric acid. It contains 35% nitrogen which is very essential for plants nutrition.
For this reason ammonium nitrate is used to prepare N-containing fertilizer that used mainly in agriculture.
For example, urea-ammonium nitrate solutions, ammonium phosphates etc. These fertilizers are known as ammonium nitrate fertilizer.
Why is ammonium nitrate dangerous?
Ammonium nitrate is a known explosive. Because it is used to makes different kinds of explosives.
But ammonium nitrate itself is not an explosive. Consequently, we can use ammonium nitrate safely.
However, under certain conditions it accidentally explodes with destructive force. For this reason, mixing ammonium nitrate with other explosives is dangerous.
For example, mixing TNT with ammonium nitrate produces a dangerous explosive called amatol.
Again the mixture of ammonium nitrate and aluminum powder produces an explosive called ammonal. For the above reason, ammonium nitrate is dangerous in nature.
