What is nitric acid?

Nitric acid

The acids are a type of substance that is characterized by a taste quite sour and exert a kind corrosive . They are substances that may come to donate a proton or cation of hydrogen to another compound. There are several types of acids in the field of chemistry, one of them is known by the name of nitric acid , a dangerous acid that can cause serious damage to humans .

Nitric acid |  What is it, characteristics, properties, benefits, uses, risksWhat is nitric acid?

The nitric acid is a type of mineral acid and toxic having very nature corrosive so it can actually cause serious damage to the contact which is used primarily as a type of reagent of laboratory and manufacturing explosives .

  • Nitric acid characteristics
  • History
  • Structure
  • Formula
  • Nomenclature
  • Nitric acid physical properties
  • Chemical properties
  • Obtaining
  • Nitric acid uses
  • Profits
  • Risks

Nitric acid characteristics

The most notable characteristics of this type of acid are the following:

  • It is obtained from the mixture of water with dinitrogen pentoxide .
  • When it is present in a solution in a proportion of more than 86%, then it is called fuming nitric acid .
  • It has a very strong odor that is also considered corrosive because it can cause burns in the respiratory tract.
  • It is an acid that has an extremely high level of combustion and for this reason, it is classified as a flammable substance .
  • When exposed to high temperatures , it releases fumes or vapors which are also toxic and dangerous.


The nitric acid is not a new acid as it was known thousands of years ago by the alchemists of the Middle Ages . However, it was not until the 12th century that a description of the substance was made in the ” De Inventioni Veritatis “, the first manuscript in history to include the preparation of the acid, by Glauber who had established that nitric acid was produced by Distillation of a mixture composed of 1 g of cyprium vitriol (CuSO4-5H2O), 1.5 g of potassium nitrate KNO3 and 0.25 g of potassium alum (KAl (SO4) 2-12H2O).

Hundreds of years later, in 1776 , Lavoisier showed that acid contained oxygen . Cavendish , in 1785 , managed to produce it by means of an electrical discharge in humid air , showing that it contained nitrogen and oxygen . Finally, the complete composition was determined by Gay-Lussac and Bethollet in the year 1816 . Its actual use became more important when sulfuric acid began to be used commercially.


Nitric acid molecules contain 3 oxygen , 1 nitrogen, and 1 hydrogen atoms. In molecules, one of the oxygen atoms is doubly bonded to the nitrogen atom in the center. Another oxygen atom is attached in a simple way to the central nitrogen atom and also in a simple way to a hydrogen atom . The last oxygen atom in the nitric acid molecule has a charge of -1 and is attached to the central nitrogen atom. How the nitrogen atom in the center of the molecule participates in four covalent bonds(with 3 oxygen atoms), it has a charge of +1.

Nitric acid |  What is it, characteristics, properties, benefits, uses, risks


Nitric acid is a nitrogenous oxo acid whose formula is HNO3 in which the nitrogen atom is attached to a hydroxyl group through bonds equivalent to the two remaining oxygen atoms.


Regarding its nomenclature, nitric acid can be named using the three systems that exist:

  • Systematic nomenclature : it is known as hydrogen trioxonitrate (V).
  • Nomenclature stock : his name is trioxonítrico acid (V).
  • Traditional nomenclature : This is the most popular and is known as nitric acid.

Nitric acid physical properties

Among the main physical properties that can be observed in nitric acid, the following are mentioned:

  • Nitric acid is physically characterized by being a liquid that has a very viscous consistency , it has no color so it is colorless and also has no odor, therefore it is odorless .
  • It has a color that ranges between yellow and brown and, when it is at room temperature, it can emit yellow fumes which have a very suffocating odor .
  • Regarding its solubility in water, it is considered as a miscible acid , which means that it can be mixed regardless of the proportion in order to form a solution .
  • Its boiling point is at 83 ° C.
  • Its melting point is -41.6 ° C.
  • It has a relative density in water of 1.4.
  • Its vapor pressure is 20 ° C: 6.4 kPa.
  • It has a molar mass of 63.012 g / mol.

Chemical properties

Its main chemical properties are:

  • It has a great oxidizing capacity .
  • When it reacts with carbide compounds , metallic powders and cyanide , it acquires a great explosive power .
  • When it is in an aqueous solution, it can completely disassociate into a NO3 ion and a hydric- type proton .
  • Being in contact with some metals such as aluminum and chromium can form an oxide layer that prevents the corrosion of chemical elements .
  • It can decompose when heated producing oxygen , nitrogen dioxide, and water .
  • It forms solid hydrates such as monohydrate (HNO3-H2O) and trihydrate (HNO3-3H2O).


Nitric acid is produced by two methods. The first method uses oxidation , condensation, and absorption to produce a weak nitric acid . Weak nitric acid can have concentrations ranging from 30% to 70% nitric acid. The second method combines dehydration , bleaching , condensation and absorption to produce a high strength nitric acid from a weak nitric acid.

  • Weak Nitric Acid Production: Much of nitric acid is made by the high temperature catalytic oxidation of ammonia . Each step corresponds to a different chemical reaction . This process usually consists of three steps:
    • ammonia oxidation
    • nitric oxide oxidation
    • absorption .
  • High Strength Nitric Acid Production : High strength nitric acid (98 to 99 percent concentration) can be obtained by concentrating weak nitric acid (30 to 70 percent concentration) by distillation. Weak nitric acid it cannot be concentrated by means of a simple fractional distillation so it must be carried out in the presence of a dehydrating agent , in this case, concentrated sulfuric acid is ideal.

The nitric acid concentration process consists of feeding strong sulfuric acid and nitric acid to the top of a dehydration column at approximately atmospheric pressure.

The concentrated nitric acid exits the top of the column as a 99% vapor, containing a small amount of NO2 and oxygen resulting from the dissociation of nitric acid. The concentrated acid vapor leaves the column and goes to a bleach and condensation system to perform the condensation of the strong nitric acid and the separation of the oxygen.

Nitric acid uses

Nitric acid is used mainly as a reagent in laboratories , for the manufacture of various types of explosives such as trinitrotoluene or TNT and cyclotrimethylenetrinitramine or RDX . It is also used to create some types of fertilizers , such as ammonium nitrate . Some of its additional uses are in the field of metallurgy and refining since it is an acid that can react with most metals.


Its main benefit occurs within the agri-food industry because thanks to this type of oxide, different types of fertilizers can be manufactured that help strengthen the roots of plants. It is used in very small quantities in the manufacture of some types of furniture and is like a product that helps to highlight pipes .


There are many risks that can occur when you are exposed to nitric acid. If contact is with the eyes , severe burns can occur as well as pain, redness and poor vision. When it touches the skin , it is very irritating and corrosive so it will also cause severe burns and injuries. If nitric acid is inhaled , the fumes and gases irritate the entire upper respiratory tract causing severe throat burns, shortness of breath and pulmonary edema in the most severe cases.

If ingested, the burns will be fatal as the membranes and mucous membranes of the mouth , esophagus and stomach will be burned. The on exposure to this acid can cause death.

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