Nitrogen Dioxide Formula: Definition, Formula & Uses

Nitrogen Dioxide Formula: Nitrogen dioxide, one of several nitrogen oxides, is a chemical compound with the formula NO₂. Often produced as an intermediate during the production of Nitric acid (for fertilisers), this smelly, unpleasant gas can be fatal in large quantities. It has been linked to pulmonary oedema or the collection of excess fluid in the lungs, acid rains etc.

As evident from the Nitrogen oxide formula, it is a bent shaped molecule that constitutes a Nitrogen atom with two oxygen atoms on either side. The distance between nitrogen and oxygen is 119.7 pm and the bond angle between the two arms is 134.4°. Continue reading the article to learn more about nitrogen dioxide and nitrogen dioxide formulas.

Nitrogen Dioxide Chemical Formula

Nitrogen dioxide is a chemical compound with the formula \({\rm{N}}{{\rm{O}}_2}\). It is one of the various nitrogen oxides that can be found in the environment. \({\rm{N}}{{\rm{O}}_2}\) is an intermediate in the industrial synthesis of nitric acid, which is produced in millions of tonnes per year for use primarily in the production of fertilisers. At higher temperatures, it transforms into a reddish-brown gas. If inhaled in large quantities, it can be fatal.

Sources of Nitrogen Dioxide

Nitrogen dioxide is rarely released directly into the atmosphere. Nitrogen dioxide is formed when nitrogen oxide \(\left( {{\rm{NO}}} \right)\) and other nitrogen oxides \(\left( {{\rm{NOx}}} \right)\) in the air react with other chemicals to form nitrogen dioxide. The combustion of fossil fuels (coal, gas, and oil), particularly fuel used in automobiles, is the primary source of nitrogen dioxide produced by human activities. It is also formed during the production of nitric acid, welding and the use of explosives, the refining of petrol and metals, commercial manufacturing, and food manufacturing. Volcanoes and bacteria are natural sources of nitrogen oxides.

Study Chemical Formula and Mole Concept

Structure of Nitrogen Dioxide

Nitrogen dioxide is known to have an electronic structure, \({\rm{O}} = {\rm{N}} \to {\rm{O}}\). Nitrogen dioxide has an unpaired electron and, therefore, behaves as a typical odd molecule. It is coloured and has a tendency to polymerize to give a colourless dimer, \({{\rm{N}}_2}{{\rm{O}}_4}\),with an even number of electrons, as shown:

The monomer, \({\rm{N}}{{\rm{O}}_2}\), is known to have an angular structure with \({\rm{ON}}\) bond angle \( = {134^{\rm{o}}}\) and \({\rm{NO}}\) distance \( = 1.18\mathop {\rm{A}}\limits^{\rm{o}}.\) The planar structures of the monomer and the dimer are shown below.

Nitrogen also forms two additional oxides, viz. nitrous oxide and nitric oxide.

Nitrogen Dioxide Gas Formula

Nitrogen dioxide is also known as nitrogen \(\left( {{\rm{IV}}} \right)\) oxide or deutoxide of nitrogen. It is a major atmospheric pollutant that helps in the absorption of \({\rm{UV}}\) rays. This oxide is a yellowish-brown liquid in its compressed form, and in its gas form, it is a reddish-brown gas. Its vapours are significantly heavier than air. The chemical formula of nitrogen dioxide gas is \({\rm{N}}{{\rm{O}}_2}\).

Preparation of Nitrogen Dioxide

Nitrogen dioxide can be prepared in many ways. Some of the ways in which nitrogen dioxide is prepared are as follows:

1. Nitrogen dioxide is typically produced by the oxidation of nitric oxide in the air by oxygen:

\(\mathop {{\rm{2NO}}}\limits_{{\rm{Nitric}}\,{\rm{Oxide}}} {\rm{ + }}\mathop {{{\rm{O}}_{\rm{2}}}}\limits_{{\rm{Oxygen}}} \, \to \,\mathop {{\rm{2N}}{{\rm{O}}_{\rm{2}}}}\limits_{{\rm{Nitrogen}}\,{\rm{dioxide}}} \)

2. Most combustion processes that use air as an oxidant produce nitrogen dioxide. Nitrogen combines with oxygen at high temperatures to form nitric oxide:

\(\mathop {{{\rm{O}}_2}}\limits_{{\rm{Oxygen}}} {\rm{ + }}\mathop {{{\rm{N}}_{\rm{2}}}}\limits_{{\rm{Nitrogen}}} \, \to \,\mathop {{\rm{2NO}}}\limits_{{\rm{Nitric}}\,{\rm{oxide}}} \)

\(\mathop {{\rm{2NO}}}\limits_{{\rm{Nitric}}\,{\rm{oxide}}} {\rm{ + }}\mathop {{{\rm{N}}_{\rm{2}}}}\limits_{{\rm{Oxygen}}} \, \to \,\mathop {{\rm{2NO}}}\limits_{{\rm{Nitrogen}}\,{\rm{dioxide}}} \)

3. Some metal nitrates, such as lead nitrate, decompose thermally, yielding \({\rm{N}}{{\rm{O}}_2}\)

\({2\rm{Pb}}{\left( {{\rm{N}}{{\rm{O}}_{\rm{3}}}} \right)_{\rm{2}}} \to \,{\rm{2PbO}}\,{\rm{ + }}\,{\rm{4N}}{{\rm{O}}_{\rm{2}}}\,{\rm{ + }}\,{{\rm{O}}_{\rm{2}}}\)

4. Nitrogen dioxide is prepared in the laboratory by the action of concentrated nitric acid on copper turnings,

\({\rm{4HN}}{{\rm{O}}_{\rm{3}}}{\rm{ + Cu}}{\mkern 1mu}  \to {\mkern 1mu} {\rm{Cu}}{\left( {{\rm{N}}{{\rm{O}}_{\rm{3}}}} \right)_{\rm{2}}}{\mkern 1mu}  + 2{\rm{N}}{{\rm{O}}_2}{\rm{ + }}{\mkern 1mu} {\rm{2}}{{\rm{H}}_{\rm{2}}}{\rm{O}}\)

5. In the laboratory, \({\rm{N}}{{\rm{O}}_2}\) can be produced in a two-step process in which nitric acid is dehydrated to produce dinitrogen pentoxide, which is then thermally decomposed to produce nitrogen dioxide.

\({\rm{2HN}}{{\rm{O}}_{\rm{3}}} \to \,{{\rm{N}}_{\rm{2}}}{{\rm{O}}_{\rm{5}}}{\rm{ + }}\,{{\rm{H}}_{\rm{2}}}{\rm{O}}\)

\({\rm{2}}{{\rm{N}}_2}{{\rm{O}}_5} \to \,4{\rm{N}}{{\rm{O}}_2}{\rm{ + }}\,{{\rm{O}}_2}\)

Properties of Nitrogen Dioxide

1. Nitrogen dioxide is a reddish-brown gas at temperatures above \(21.2\,^\circ {\rm{C}}\) with a pungent, acrid odour, becomes a yellowish-brown liquid at temperatures below \(21.2\,^\circ {\rm{C}},\) and converts to a colourless dinitrogen tetroxide at temperatures below \( – 11.2\,^\circ {\rm{C}}.\)

2. The length of the bond between the nitrogen and oxygen atoms is \(119.7{\rm{pm}}\). This bond length corresponds to a bond order of one and two.

3. The ground electronic state of nitrogen dioxide, unlike ozone, is a doublet state.

4. The molar mass of nitrogen dioxide is \(46.006\;{\rm{g}}/{\rm{mol}}\).

5. The density of nitrogen dioxide is \(1.880\;{\rm{g}}/{\rm{L}}\).

6. The melting and boiling point of nitrogen dioxide is \( – 9.3\,^\circ {\rm{C}}\) and \(21.15\,^\circ {\rm{C}},\) respectively.

7. It is soluble in water. Its aqueous solution is a mixture of nitrous acid and nitric acid.

\({\rm{2N}}{{\rm{O}}_{\rm{2}}}\left( {\rm{g}} \right){\rm{ + }}{{\rm{H}}_{\rm{2}}}{\rm{O}}\left( {\rm{l}} \right){\mkern 1mu}  \to {\mkern 1mu} {\rm{HN}}{{\rm{O}}_{\rm{2}}}\left( {{\rm{aq}}} \right){\rm{ + HN}}{{\rm{O}}_3}\left( {{\rm{aq}}} \right)\)

8. It is acidic in nature. It reacts with sodium hydroxide to form a mixture of sodium nitrite and sodium nitrate.

\({\rm{2N}}{{\rm{O}}_{\rm{2}}}\left( {\rm{g}} \right){\rm{ + NaOH}}\left( {{\rm{aq}}} \right){\mkern 1mu}  \to {\mkern 1mu} {\rm{NaN}}{{\rm{O}}_{\rm{2}}}\left( {{\rm{aq}}} \right){\rm{ + NaN}}{{\rm{O}}_3}\left( {{\rm{aq}}} \right) + {{\rm{H}}_{\rm{2}}}{\rm{O}}\left( {\rm{l}} \right)\)

9. Nitrogen dioxide acts as both a reducing and oxidising agent. It decolourises acidified potassium permanganate.

\({\rm{2KMn}}{{\rm{O}}_4}\left( {\rm{g}} \right){\rm{ + 3}}{{\rm{H}}_2}{\rm{S}}{{\rm{O}}_4} + 10{\rm{N}}{{\rm{O}}_2} + {\rm{2}}{{\rm{H}}_2}{\rm{O}}\, \to \,{{\rm{K}}_2}{\rm{S}}{{\rm{O}}_4}{\rm{ + 2MnS}}{{\rm{O}}_4} + {\rm{10HN}}{{\rm{O}}_3}\)

It oxidises Sulphur dioxide to sulphuric acid.

\({\rm{S}}{{\rm{O}}_{\rm{2}}}\left( {\rm{g}} \right){\rm{ + }}{{\rm{H}}_2}{\rm{O}}\left( {\rm{l}} \right){\mkern 1mu}  + {\rm{N}}{{\rm{O}}_{\rm{2}}}\left( {\rm{g}} \right)\, \to \,{{\rm{H}}_2}{\rm{S}}{{\rm{O}}_4}\left( {{\rm{aq}}} \right) + {\rm{NO}}\left( {\rm{g}} \right)\)

Uses of Nitrogen Dioxide

1. Nitrogen dioxide can be used as an intermediate in the production of nitric acid and in the production of oxidised cellulose compounds.
2. It can also be used as an oxidising agent.
3. It can be used as a catalyst as well as an intermediate in the production of sulfuric acid.
4. It can also be used as an oxidizer for rocket fuels as well as a nitrating agent.
5. Nitrogen dioxide can also be used to make explosives.

The Harmful Effect of Nitrogen Dioxide on Health

Nitrogen dioxide has the greatest health impact on the respiratory system. Children inhaling nitrogen dioxide increase their risk of respiratory infection and may result in poorer lung function later in life. Nitrogen dioxide concentrations in the air have also been linked to an increase in mortality and hospitalizations for respiratory disease. Nitrogen dioxide can weaken the lungs’ defences against bacteria, making them more vulnerable to infection. Asthma can also be aggravated.

Summary

Nitrogen dioxide is a chemical compound with the formula \({\rm{N}}{{\rm{O}}_2}\). It is one of the various nitrogen oxides that can be found in the environment. Nitrogen dioxide concentrations in the air have also been linked to an increase in mortality and hospitalizations for respiratory disease. Nitrogen dioxide can be used as an intermediate in the production of nitric acid and in the production of oxidised cellulose compounds as an oxidising agent and used to make explosives.

FAQs on Nitrogen Dioxide Formula

Q.1. How is Nitrogen dioxide formed?
Ans: Nitrogen dioxide can be formed in many ways. One of the ways to produce nitrogen dioxide is by the oxidation of nitric oxide in the air by oxygen.

\(\mathop {{\rm{2NO}}}\limits_{{\rm{Nitric}}\,{\rm{Oxide}}}  + \mathop {{{\rm{O}}_{\rm{2}}}}\limits_{{\rm{Oxygen}}} \, \to \,\mathop {{\rm{2N}}{{\rm{O}}_{\rm{2}}}}\limits_{{\rm{Nitrogen}}\,{\rm{dioxide}}} \)

Q.2. What is the formula for Nitrogen?
Ans: The formula of nitrogen is \({{\rm{N}}_2}.\)

Q.3. Why is nitrogen dioxide bad?
Ans: Nitrogen dioxide levels that are too high can harm the human respiratory tract and increase a person’s susceptibility to, and severity of, respiratory infections and asthma.

Q.4. What is the symbol of nitrogen gas?
Ans: The symbol of nitrogen gas is \({{\rm{N}}_2}.\)

Q.5. What are the \(5\) uses of nitrogen?
Ans: The five uses of nitrogen are as follows:
a. It is used to make nitric acid.
b. It is used in making fertilisers.
c. It is used in the manufacture of ammonia.
d. It is used in making explosives
e. It is used in the production of dyes.

Q.6. What is the main source of nitrogen dioxide?
Ans: The combustion of fossil fuels is the primary source of nitrogen dioxide.

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