Nitric Acid Properties (23 Facts You Should Know)

Nitric acid is a strong acid composed of hydrogen, nitrogen, and oxygen. Let us discuss the chemical properties of nitric acid.

Nitric acid is an inorganic solution and highly corrosive in nature. Nitric acid is used in the preparation of ammonium nitrate and is the main component of various fertilizers. If the solution contains more than 86% of nitric acid then it is known as fuming nitric acid.

This editorial discusses the CAS number, molar mass, IUPAC name, melting point, boiling point, oxidation state, and many more properties of nitric acid solution.

Nitric acid IUPAC name

The IUPAC name of nitric acid is nitric acid itself.

Nitric acid chemical formula

The chemical formula of nitric acid is HNO3, which contains a central nitrogen atom, 1 oxygen atom connects to N with a double bond, another O atom, and the OH group is attached to N with a single bond.

Nitric acid chemical formula

Nitric acid CAS number

The CAS number for HNO3 is 7697-37-2.

Nitric acid ChemSpider ID

The ChemSpider ID of HNO3 is 919.

Nitric acid chemical classification

HNO3 is classified as an acidic solution. Nitric acid changes red litmus paper to blue confirming its acidic nature.

Nitric acid molar mass

The HNO3 has a molar mass of 63.01 g/mole.

Nitric acid color

HNO3 is a colorless transparent liquid solution, but if it stores for a long time it shows yellowish color due to decomposition into nitrogen oxides.

Nitric acid viscosity

The viscosity of HNO3 is 1.092 mPa.s at 0 degree Celsius, 0.746 mPa.s at 25 degree Celsius; 0.617 mPa.s at 40 degree Celsius.

Nitric acid molar density

The molar density of HNO3 is 1.413 g/ml at 25°C.

Nitric acid melting point

The melting point value of HNO3 is −42 °C (231 K, −44 °F).

Nitric acid boiling point

The boiling point value of HNO3 is 83 °C (356 K, 181 °F) and the 68% nitric acid solution boils at 121 °C (394 K, 250 °F).

Nitric acid state at room temperature

HNO3 is a liquid solution compound at room temperature.

Nitric acid covalent bond

HNO3 is composed of strong covalent bonds. All the elements N, H, and O of HNO3 are connected with each other by 2 single and 1 double covalent bond. The covalent bond is a strong bond due to the sigma bond.

Nitric acid oxidation state

The oxidation state of the Nitrogen atom of HNO3 in the nitrate group is +5.

Nitric acid acidity/alkaline

HNO3 is a strong acid in nature. It is a monoprotic acid and on ionization, it can completely ionize in water. It has a pH value of approximately 3 which confirms its acidic character.

Is nitric acid odorless?

HNO3 has a sharp odor thus it is not odorless.

Is nitric acid paramagnetic?

HNO3 is a diamagnetic compound. It has a magnetic susceptibility value of −1.99×10−5 cm3/mol. The negative value of nitric acid magnetic susceptibility confirms its diamagnetic nature.

Nitric acid hydrates

HNO3 hydrate shows two or more hydrates. The nitrate hydrate with chemical formula H3NO4 is a monohydrate of nitric acid and nitric acid hydrate with formula H4N2O7 is another hydrate of nitric acid.

Nitric acid crystal structure

HNO3 nitric acid cannot form a crystal structure as it is a covalent liquid compound and not a solid ionic compound.

Nitric acid polarity and conductivity

  • HNO3 is a polar compound due to more electronegativity between its atoms.
  • The conductivity of HNO3 is 862.0 at 25 degree Celsius.

Nitric acid reaction with acid

HNO3 can be mixed with acids like sulfuric acid and hydrochloric acid. When nitric acid is added to H2SO4 reacts vigorously and forms dark brown fumes of the nitrating mixture. Also, nitric acid reacts with HCl and produces nitrosyl chloride with chlorine gas and water.

HNO3 + 2 H2SO4 H3O+ + NO2+ + 2 HSO4

HNO3 + 3 HCl NOCl + Cl2 + 2 H2O

Nitric acid reaction with base

HNO3 reacts with a base like sodium hydroxide (NaOH) undergoes a neutralization reaction and forms sodium nitrite and water. Here, sodium ions of NaOH join with nitrate ions of HNO3, and hydrogen ions of HNO3 join with hydroxide ions of NaOH.

NaOH + HNO3 NaNO3 + H2O

Nitric acid reaction with oxide

HNO3 can react with metal oxides. When nitric acid reacts with metal oxides like copper oxide (CuO) produces copper nitrate Cu(NO3)2 and water.

CuO + 2 HNO3 → Cu(NO3)2 + H2O

Nitric acid reaction with the metal

HNO3 reacts with metals and forms metal salts with nitrogen oxide and water. Except for manganese and magnesium which react with dilute HNO3 and form salt and hydrogen. The reactions of nitric acid with copper metal and magnesium metal are given below.

3 Cu + 8 HNO3 → 3 Cu(NO3)2 + 2 NO + 4 H2O

Mg + 2 HNO3 → Mg(NO3)2 + H2


Nitric acid is a colorless or pale yellow color inorganic solvent. The chemical formula of nitric acid is HNO3 and has CAS number 7697-37-2. The molar mass of HNO3 is 63.01 g/mole. It can react with acids, bases, metal oxides, and metal elements.