Oxides of Nitrogen

Overview

• Nitrogen is the seventh element in the periodic table, following carbon and oxygen. It is an essential component of amino acids.
• Nitrogen gas accounts for approximately 80% of the Earth’s atmosphere.
• It is a colourless, primarily diatomic nonmetal gas that is odourless and colourless in nature.
• Most of its compounds are trivalent because it contains five electrons in their outer shell.
• It is found in all living tissues.
• It is a necessary component of life since it is a component of DNA and a part of a genetic code.
• It can be found in soil and water as nitrates and nitrites.
• All of these chemicals are linked and part of the nitrogen cycle.
• Industrial enterprises generate a lot of nitrogen, which increases the nitrite and nitrate levels in the ground and water as a result of nitrogen cycle processes.
• Important chemicals found in nitric acid salts include potassium nitrate, ammonium nitrate, and nitric acid. Nitro glycerine and other nitrated organic compounds are frequently used as explosives.
• Liquid nitrogen is used as a refrigerant in food transportation and freezing. Liquid nitrogen is also used in the preservation of bodies and reproductive cells, as well as the stable storage of biological materials.
• Nitrogen reacts with oxygen under various conditions to generate a multitude of binary oxides that differ depending on the oxidation state of the nitrogen atom. They vary from N₂O (N =+1 oxidation state) through NO (+2), N₂O₃ (+3), N₂O₄ (+4), and N₂O₅ (+5). The propensity of oxides to generate pπ- pπ multiple bonds determines their structures.

Nitrous Oxide (N₂O)

• Ammonium nitrate is heated to make nitrous oxide.

NH₄NO₃→N₂O+2H₂O

• It is a colourless, unreactive gas with a pleasant odour. It is also known as laughing gas because, when inhaled in little amounts, it generates uncontrollable laughter.
• It’s a neutral oxide that combines with sodamide to generate sodium azide.

N₂O+2NaNH₂→NAN₃+NH₃+NaOHer

• It functions as an anaesthetic in short doses for minor surgeries.
• At 873K, it decomposes into nitrogen and oxygen. As a result, it aids combustion by functioning as an oxygen source.

2N₂O→2N₂ + O₂

Nitric Oxide (NO)

• It is produced by the catalytic oxidation of ammonia in the presence of platinum at 1100 K.

4NH₃ + 5O₂ → 4NO + 6H₂O

• It can also be made by reacting nitric acid with copper as follows:

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

• It can also be synthesized by reducing sodium nitrite with ferrous sulfate in the presence of sulfuric acid.

Fe₂(SO4)₃ + 2NaHSO₄ + 2H₂O + 2NO → 2NaNO₂ + 2FeSO₄ + 3H₂SO₄

• It is an oxide that is neutral.
• It is an odourless, colourless gas. Because it possesses an odd number of electrons (11 valence electrons), it is paramagnetic in the gaseous form. However, in the liquid and solid stages, it forms a loose dimer that cancels the magnetic effects of two unpaired electrons. It has diamagnetic properties.
• Nitric oxide quickly combines with oxygen to produce brown nitrogen dioxide emissions.

2NO (g) + O₂ (g) →2NO₂ (g)

Dinitrogen Trioxide (N_₂O₃)

• It is made by chilling equimolar amounts of nitric oxide and nitrogen dioxide to temperatures below 253 K.

NO(g) + NO₂ (g) → N₂O₃

• It may also be made by reacting nitric oxide and dinitrogen tetraoxide at 250 degrees Celsius.

2NO + N₂O₄ →2N₂O₃

Dinitrogen Trioxide Properties:

• It is a blue solid with acidic chemistry. It is nitrous acid anhydride (HNO₂).

N₂O₃ + H₂O →2HNO₂

• It only exists in its pure form as a solid at extremely low temperatures. It dissociates into NO and NO₂ above its melting point (273 K). NO + NO₂ →N₂O₃

Nitrogen Dioxide (NO₂)

• It is made by heating dried lead nitrate in a stainless steel reaction tank.

2Pb(NO₃)₂→2PbO+4NO₂+O₂

• It is also an odd electron molecule that occurs in gas phase equilibrium with N 2O4 as:

N₂O₄⇔2NO₂

• Above 415 K, it is mostly NO, while below 250 K, it is mostly N₂O₄.

2NO₂⇔N₂O₄

Dinitrogen Pentaoxide (N₂O₅)

• It is made by combining strong nitric acid with phosphorus pentoxide and dehydrating it.

2N₂O₅+ HPO₃ →4HNO₃ + P₄O₁₀.

• Below 273K, N₂O₅ occurs as a colourless solid. The colour changes to yellow as the temperature rises due to the partial breakdown of colourless N₂O₅ to brown NO₂.

2 N₂O₅ →4NO₂ + O₂

• At 303 K, the crystals melt, releasing a yellow liquid that decomposes at 313 K to produce NO₂.
• N₂O₅ is a powerful oxidizing agent that oxidizes iodine to I₂O_5.
• The elements NO and NO₂ are utilized in the production of nitric acid and nitrate fertilizers. Liquid N₂O₄ is also utilized as an oxidizer in rocket fuels used in missiles and space vehicles. Because of its toxic nature, NO produces pollution in the atmosphere. Its vapours are discharged into the atmosphere when oil and coal are burned.

FAQ’s

Is nitrogen oxide dangerous?

Nitrogen dioxide is an aggravating gas that, in large concentrations, irritates aircraft routes. When nitrogen is released after fuel combustion, it combines with oxygen iotas to form nitric oxide (NO). This combines with oxygen to form nitrogen dioxide. Nitric oxide is not regarded to be hazardous to health in ordinary surroundings, although nitrogen dioxide can be. Nitrogen dioxide and nitric oxide are referred to together as nitrogen oxides (NOx). NOx gases react to create brown haze and acid rain, as well as being essential in the formation of fine particles (PM) and ground-level ozone, all of which are linked to unfavourable health effects.

Is NOx considered a greenhouse gas?

Nitrogen oxides are a class of gases composed of nitrogen and oxygen. Nitric oxide and nitrogen dioxide are two of the most well-known nitrogen oxides. Nitric oxide has the chemical formula NO, while nitrogen dioxide has the formula NO2. Nitrous oxide, or N2O, is a greenhouse gas that contributes to climate change.

How do nitrogen oxides form?

In locations with heavy engine vehicle traffic, such as large urban areas, the number of nitrogen oxides emitted into the atmosphere as air pollution can be significant. NOx gases are formed whenever ignition occurs in the presence of nitrogen, for example, in automobile engines; they are also produced by lightning.