Nitric Acid: Its Role and Reactions in Chemistry
by Yuvi K - December 23, 2023
Nitric Acid: Its Role and Reactions in Chemistry
Nitric acid, also known as aqua fortis and spirit of niter, is an aqueous solution of hydrogen nitrate and a strong mineral acid. Nitric acid has a distinctive pungent odour, is colorless and extremely corrosive. It is an important component of the chemical industry, being used in the production of ammonium nitrate for fertilisers, plastics, paints, dyes, synthetic fibers, inorganic nitrates and active pharmaceutical ingredients.
Nitric acid is used in many industrial processes, such as surface etching and cleaning of electronic parts, and for metal plating. Its wide range of uses in organic chemistry can be attributed to its strong oxidising properties and its ability to act as both an acid and a base. In this article we will look at the role and reactions of nitric acid in chemistry.
Composition and Reaction of Nitric Acid
Nitric acid is composed of two major components – hydrogen nitrate and water. It is a strong acid with a pKa of -1.41 and an acidity constant Ka that corresponds to 10^-1.9. It can be considered to be a strong acid due to its dielectric constant of 4.8 and its boiling point of 83.2°C.
The simplest reaction of nitric acid is the reaction with water, whereby an equilibrium is established between the two substances:
HNO3 + H2O ⇌ H3O+ + NO3-
As nitric acid can behave both as an acid and a base, it can also react with other strong acids such as sulfuric acid or hydrochloric acid or with weak bases such as ammonia or carbonates:
HNO3 + HCl ⇌ Cl- + H3O+ + NO2
HNO3 + NH3 ⇌ NH4+ + NO3-
HNO3 + Na2CO3 ⇌ NaNO3 + H2CO3
Applications of Nitric Acid in Chemistry
Nitric acid has many uses in chemistry and other industries. It is used in laboratories to prepare stocks and solutions of other acids such as acetic acid, hypochlorous acid and hydrochloric acid. It can also be used in the preparation of precipitates, oxidation reactions, the preparation of metals and metal compounds and the production of nitrates.
It is also used in the manufacturing process of many products. It is used to make synthetic fibres and dyes, explosives, pharmaceuticals, and cleaning agents. Nitric acid also serves as an effective catalyst in organic reactions such as hydrolysis and amination, and is used in the production of nitro compounds.
Nitric acid is widely used in the production of ammonium nitrate for fertilisers, as it decomposes to form ammonium ions and nitrate ions:
HNO3 ⇌ 1/2N2 + 2H+ + 2NO3-
The nitrate ions produced in this reaction can be used to make fertilisers, explosives and other industrial applications.
Saftey Precautions and Hazards of Using Nitric Acid
Nitric acid is a strong and hazardous inorganic acid, and it must be handled with care. It is highly corrosive and can cause skin burns and irritation to the eyes and respiratory passages. It is recommended to wear safety glasses and gloves when working with it. It should also be stored in a cool, well-ventilated area.
Nitric acid should never be mixed with incompatible chemicals such as flammable and combustible materials, organic substances, reducing agents and alkali metals. As it is a strong oxidising acid, contact with combustible materials can cause explosions.
Conclusion
Nitric Acid is an important component of the chemical industry. It is used for a wide range of industrial processes such as surface etching, cleaning, metal plating and in the production of fertilisers, explosives, plastic explosives and dyes. It is also used in laboratories for the preparation of other acids or to catalyse organic reactions.
Safety precautions must always be observed when working with nitric acid due to its hazardous and corrosive nature. It must be handled with care and always be stored in a cool, well-ventilated area. It should also never be mixed with other incompatible chemicals.
