A Quick Note on Properties of Nitric Acid

Nitric acid is a colorless, fuming, and highly corrosive liquid that is a common laboratory reagent and an important industrial chemical for the manufacture of fertilizers and explosives. It has a boiling point of 84.1 degrees Celsius and freezes at -41.55 degrees Celsius. It forms a kind of white solid after that. Its chemical name is HNO3 and acts as a strong oxidizing agent in its concentrated state. 

What Is Nitric Acid All About?

This colorless liquid is a strong acid that has the chemical formula of HNO3 (Strong oxidizing). It is also known as the spirit of niter or aqua fortis, apart from colorless acid. Although it is colorless in its pure form, as gradually it gets older it turns into a yellow shade. This color change is due to the process of decomposition that the Nitric acid goes through the oxides of nitrogen and water. It is very corrosive and dangerously toxic. It harms the skin and causes severe skin burns. To form nitrate salts, it reacts with hydroxides and even metals. HNO3 is used as a strong oxidizing agent. It can be manufactured by ammonia (catalyzing effect). It is a common reagent used in labs and an important chemical used in industries and factories to create explosives and fertilizers. The pH of Nitric acid is approx. 3.01.

Uses Of The Nitric Acid

Nitric acid is mainly used to make ammonium nitrates to manufacture plastic, dye, and fertilizers from its products.

1. It is used in creating explosives such as TNT etc.

2. It is used in rockets which are liquid-fueled as an oxidizer.

3. When it’s in pure form, it is used to also remove the wart.

4. It is also used as a chemical doping agent in electrochemistry industries.

Chemical Properties Of HNO3

Nitric acid is naturally a very strong acid and turns blue litmus red.

Nitric acid decomposes when standing in its still form, leading to the formation of brown nitrogen dioxide. This is the reason why it becomes brownish over time even though we know that fresh nitric acid is colorless.

4HNO3 → 4NO2 + O2 + 2H2O

Nitric acid releases hydrogen gas with metals up the hydrogen level in the metal activity part.

Mg + 2HNO3 → Mg (NO3)2 + H2

and

Mn + 2HNO3 → Mn (NO3)2 + H2

Molecular Structure

The colorless liquid’s molecules contain 3 oxygen atoms, 1 nitrogen atom, and 1 hydrogen atom. In the HNO3 atomic molecules, one of the oxygen atoms is bonded doubly to the nitrogen atom in the center. The next oxygen atom is singly bonded to the central nitrogen atom and singly bonded to a hydrogen atom. The last oxygen atom in the nitric acid atom has a charge of -1 and is again singly bonded to the nitrogen atom in the center. As the nitrogen atom at the center of the molecule is taking part in four covalent bonds with the other 3 oxygen atoms, it has a charge of +1. So, the net charge on the nitric acid molecule is in actuality 0 as the positive charge on the nitrogen atom and the negative charge on the oxygen atom cancel each other out. It is to be noted that the charges in these molecules cannot be localized due to their resonance. Nitric acid decomposes itself into the water, nitrogen dioxide, and oxygen, and forms a brownish-yellow solution. It is a strong acid, and it is ionized into hydronium (H3O+) and nitrate (NO3−) ions in an aqueous solution HNO3 is a powerful oxidizing agent and acts as an electron acceptor in an oxidation-reduction reaction. Among the many important reactions of it are neutralization with ammonia to make ammonium nitrate which is a major component in fertilizers and nitration of glycerol and toluene which forms the explosives nitroglycerin and trinitrotoluene (TNT), and the preparation of nitrocellulose, and oxidation of metals to the respective oxides or nitrates.

Origin and Experimenting 

The preparation and use of nitric acid were known from the ancient alchemist’s era. A common lab process that has been used for many years was told to a German chemist, Johann Rudolf Glauber (1648), who had the process of heating potassium nitrate with concentrated sulfuric acid. And in 1776 Antoine-Laurent Lavoisier proved that it also contained oxygen, and in 1816 Joseph-Louis Gay-Lussac and Claude-Louis Berthollet proved its chemical composition to everyone. The main method of manufacturing nitric acid is the catalytic oxidation of ammonia that we already discussed ahead. In the method discovered by the German chemist Wilhelm Ostwald in 1901, ammonia gas is succeeded by oxidation to nitric oxide and nitrogen dioxide by air or oxygen in the presence of a platinum gauze catalyst. The nitrogen dioxide is absorbed in water to make nitric acid. This results in an acid-in-water solution that is about 50–70 percent by weighted acid and can be dehydrated by the distillation process with sulfuric acid.

Conclusion

Nitric acid is a colorless, fuming, and highly corrosive liquid that is a common laboratory reagent and an important industrial chemical for the manufacture of fertilizers and explosives Nitric acid decomposes when standing in its still form, leading to the formation of brown nitrogen dioxide. This is the reason why it becomes brownish over time even though we know that fresh nitric acid is colorless.