Nitrite Formula

What is Nitrite Formula?

A nitrite ion is an inorganic compound that is composed of nitrogen and oxygen. Let us discuss the nitrite ion formula. The chemical formula for the nitrite ion is NO2-. In food industries, nitrite of Sodium is commonly employed as a curing agent. Sodium nitrite or nitrate is responsible for the colour and flavour of cooked cured meats. In nature, the nitrite anion is a common intermediary in the nitrogen cycle. Nitrite also refers to chemical molecules containing the -ONO group, which are nitrous acid esters.


Chemical Elements Used in Writing Formula for Nitrite

The Elements that are included in the formula for nitrite are Nitrogen and Oxygen. For writing its formula a clear idea of the valencies of both nitrogen and oxygen is required.


Nitrite Structure 

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As we know, the symbol of nitrite is NO2-. The nitrite ion has a symmetrical structure (C2v symmetry), with equal length N–O links and a bond angle of roughly 115 degrees. It's described as a resonance hybrid in valence bond theory, with equal contributions from two canonical forms that are mirror reflections of one another. There is a sigma bond between each oxygen atom and the nitrogen atom in molecular orbital theory, as well as a delocalized pi link generated from the p orbitals on nitrogen and oxygen atoms that is perpendicular to the molecule's plane. The ion's negative charge is evenly divided between the two oxygen atoms. A lone pair of electrons is carried by both nitrogen and oxygen atoms. The nitrite ion is thus a Lewis base.


Properties of Nitrite 

  • Acid-Base Properties of Nitrite Ion

The conjugate base of the weak acid nitrous acid is nitrite:

HNO2H+ + NO2-;      pKa ≈ 3.3at 18 °C

  • Nitrous Acid is Also Extremely Volatile, Mostly Existing as a Trans-Planar Molecule in the Gas Phase. it Is Unstable in Solution in Terms of the Disproportionation Reaction:

3HNO2 (aq) ⇌ H3O+ + NO3- + 2NO

At 0 °C, this reaction is sluggish. Making nitric oxide (NO) in the lab involves adding acid to a nitrite solution in the presence of a reducing agent, such as iron(II).

  • Oxidation and Reduction

The nitrogen atom in nitrite has a formal oxidation state of +3. This means it can be oxidised to +4 and +5 oxidation levels, or reduced to oxidation levels as low as 3. The table below shows the standard reduction potentials for processes that directly involve nitrous acid: Consider the following scenario:

H2N2O2 + 2 H+ + 2 e-N2 + 2 H2O;      E0 = +2.65 V

When nitrogen is in the oxidation state +5, oxidation reactions usually result in the creation of the nitrate ion. For quantitative analysis of nitrite (by titration), for example, oxidation with permanganate ion can be used:

5 NO2- + 2 MnO4- + 6 H+ → 5 NO3- + 2 Mn2+ + 3 H2O

Reduction reactions with nitrite ion produce a variety of products, depending on the reducing agent and its intensity. With sulphur dioxide, the products are NO and N2O; with tin(II) (Sn2+), the product is hyponitrous acid (H2N2O2); and with hydrogen sulphide, the product is ammonia (NH3). The result of nitrite reduction with the hydrazinium cation (N2H5+) is hydrazoic acid (HN3), an unstable and explosive compound:

HNO2 + N2H5+ → HN3 + H2O + H3O+

which can also react with nitrite in the following way:

HNO2 + HN3N2O + N2 + H2O

This reaction is unique since it incorporates nitrogen molecules in four different oxidation states.

Did You Know?

  • The preservative sodium nitrite protects ham, salami, and other processed and cured meats from dangerous microorganisms while also giving them their pink hue. However, nitrite can damage cells and develop into cancer-causing chemicals in the human body under specific situations.

  • The oral fatal dose for humans was estimated to be between 33 to 250 mg of nitrite per kilogram of body weight, with lower dosages being used for children and the elderly.

FAQs (Frequently Asked Questions)

Question1: What is the Formula of Nitrite? What are Its Uses?

Answer: The nitrite ion formula is NO2-.  The uses of nitrite are given below:

  • It is used as a counter ion in various reactions.

  • It is used as a preservative.

  • It is used as an antidote for cyanide poisoning treatment.

Question2: Is the Chemical Formula of Nitrite Ion and Molecular Formula of Nitrite Same? Explain the Role of Nitrite in Cancer.

Answer: Yes the chemical and molecular formula for nitrite is the same. Nitrite can harm cells and transform into cancer-causing chemicals in the human body under specific conditions. Nitrate and nitrite can react with amines and amides in the body to generate N-nitroso compounds (NOC), which have been shown to cause cancer in animals and may cause cancer in humans when consumed through drinking water and other food sources.