How Does Nitrogen Trioxide Behave Chemically?
Nitrogen trioxide (molecular formula N2O3) is a chemical compound formed by mercury and chlorine. It is also known as dinitrogen trioxide or nitrogen sesquioxide. The compound is highly toxic and irritates the mucous membranes. Nitrogen trioxide is a blue liquid accompanied by a sharp and unpleasant chemical odour. Density 1.447 g / cm3. Due to the low-boiling point of 3.5 degrees C, the compound is held as a liquid by compression. Partially dissociates into NO and NO2. Strong irritant to skin, eyes and mucous membranes. Vapours are very toxic by inhalation. They are used in special-purpose fuels. The prolonged exposure to heat may cause the container to rupture violently and burst out.
\[NO + NO_{2} \rightleftarrows N_{2}O_{3}\]
Properties of Nitrogen Trioxide N2O3
Nitrogen trioxide (molecular formula N2O3) has a molecular weight of 76.012 g / mol and a density of 1.447 g / cm3. It has a hydrogen bond donor count of 0 while the hydrogen bond donor count is 4. The boiling point and melting point of nitrogen trioxide is 3.5 degrees Celsius and -100.7 degree Celsius.
Some other properties of nitrogen trioxide N2O3 are mentioned below:
XLogP3-AA – -0.1
Rotatable Bond Count - 0
Exact mass - 75.990892 g / mol
Monoisotopic Mass - 75.990892 g / mol
Topological Polar Surface Area - 75.2 Å2
Heavy Atom Count – 5
Complexity – 50.4
Covalently-Bonded Unit Count – 1
Compound Is Canonicalized – Yes
Solubility in water – Yes
Uses of Nitrogen Trioxide
Properties of Nitrogen Trioxide N2O3 is used in the following ways:
Due to its highly explosive nature, it is used as a particular fuel.
It supports the only combustion and only helps in burning, but does not burn itself which may ignite substances like wood, paper, oil, clothing, etc.
It is a powerful oxidizer.
It is combined with other chemical compounds to be used as an oxidizing agent.
It is also used in the chemical industry, such as in making nylon, dyes, etc.
Structure of Nitrogen Trioxide
Nitrogen – nitrogen (N – N) bonds are almost the same in length as that in hydrazine, that is, 145 pm. However, Dinitrogen trioxide has a long N–N bond of 186 pm, which is unusual. Some nitrogen oxides contain long N–N bonds, which include dinitrogen tetroxide (175 pm). The Nitrogen Trioxide molecule has a planar structure and exhibits Cs symmetry.
It produces unstable nitrous acid (HNO2) when mixed into water. An alternative structure for the true anhydride, i.e. O=N–O–N=O, but this isomer is not observed. If the nitrous acid produced is not used up quickly, then it decomposes into nitric oxide and nitric acid. Sometimes, nitrite salts are produced by adding N2O3 to solutions of some bases like NaOH.
(Image will be uploaded soon)
Handling and Storage
For non-fire spills and leaks, fully encapsulating, vapour-protective garments should be worn. It is not advisable to touch or walk over spilling material. Keep flammables (oil, wood, paper, etc.) away from the spilt substance. If you can do so without putting yourself in danger, stop the leak. To minimize vapours or deflect vapour cloud drift, use water spray. Allowing water runoff to come into touch with spilt substances is not a good idea. Water should not be directed at the spill or the source of the leak. If at all possible, flip leaky containers so that gas instead of liquid escapes. Prevent access to rivers, sewers, basements, and other restricted locations. Isolate the area till the gas has passed. Make certain that the area is adequately ventilated.
Personal Protection and Exposure Control
Wear self-contained breathing equipment with positive pressure (SCBA). Wear chemical protection clothes that the manufacturer has particularly suggested. It may or may not give any heat protection. Protective apparel worn by structural firefighters provides very limited protection in fire circumstances; it is ineffective in spill scenarios when direct contact with the chemical is possible.
Fire Fighting Measures
These items do not burn but will aid in the combustion process. Allow the fire to burn without being extinguished. If fire must be extinguished, it is best to use water spray or fog. Only water; no dry chemicals, CO2, or Halon®. Make sure that water doesn’t enter the containers. Move containers away from the fire zone if you can do so safely. Damaged cylinders should only be handled by experts. Fight fires from as far away as possible or utilize unmanned hose holders or monitor nozzles. Cool containers with large amounts of water until the fire has been extinguished. Water should not be directed at the source of the leak or safety devices; icing may develop. Withdraw immediately if there is a rising sound from the venting safety mechanisms or if the tank is discoloured. Always keep a safe distance from engulfed-in-fire tanks. For severe flames, use unmanned hose holders or monitor nozzles; if this isn't possible, just leave the area and let the fire burn.
Solved Examples
Q. Nitrogen Trioxide (N2O3) is/has a _ While Nitrogen Dioxide (NO2 ) is/has a _.
a. Brown gas, Blue gas
b. Colourless solid, brown gas
c. Colourless solid, colourless gas
d. Blue solid, Brown gas
Solution:
Dinitrogen trioxide (N2O3 ) is solid in blue colour. Nitrogen has an oxidation number of +3 while NO2 is gas in brown colour. The oxidation number of nitrogen in the compound is +4. Therefore, the answer is 4.
Q. Assertion: N2O3 is Less Basic than P2O3.
Reason: As we go down the group, the metallic nature increases.
a. The reason is the correct explanation of assertion and both assertion and reason are true.
b. The reason is not the correct explanation of assertion and both assertion and reason are true.
c. The reason is false and the assertion is true.
d. The assertion is not true and the reason is true.
Solution: When we go down the group, atomic radius increases, due to this ionization energy decreases and hence a tendency to lose electrons also increases (i.e., the metallic character is increased).
Since metallic characters increase down the group, the basicity increases down the group.
Hence the order of basicity is N2O3 <P2O3.
Therefore, the answer is 1.
Q. What is the Chemical Formula of Nitrogen Trioxide?
Solution: The chemical formula of nitrogen trioxide is N2O3.
FAQs on Nitrogen Trioxide (N2O3): Properties, Structure & Applications
1. What is Nitrogen Trioxide?
Nitrogen Trioxide, also known as Dinitrogen Trioxide or Nitrogen Sesquioxide, is an inorganic chemical compound with the formula N₂O₃. It is a deep blue liquid or solid that is highly unstable at room temperature. As one of the binary oxides of nitrogen, it is formed from two nitrogen atoms and three oxygen atoms and is notable for its role as the anhydride of nitrous acid.
2. What are the key physical and chemical properties of Nitrogen Trioxide?
Nitrogen Trioxide (N₂O₃) exhibits distinct properties:
- Physical Properties: It is a deep blue liquid or solid with a low boiling point of 3.5°C. It has a sharp, pungent odour and is highly volatile.
- Chemical Properties: It is chemically unstable and readily decomposes into nitric oxide (NO) and nitrogen dioxide (NO₂). It reacts with water to form nitrous acid (HNO₂), making it an acid anhydride. It is a strong oxidising agent.
3. How is Nitrogen Trioxide typically prepared?
The most common method for preparing Nitrogen Trioxide is by mixing equal parts of nitric oxide (NO) and nitrogen dioxide (NO₂). The mixture is then cooled to below -21°C, which causes the gases to combine and condense into the deep blue liquid N₂O₃. The reaction is reversible and can be represented as: NO + NO₂ ⇌ N₂O₃.
4. What are the main uses of Nitrogen Trioxide?
Due to its instability, the uses of Nitrogen Trioxide are limited and highly specialised. Its primary application is as a potent oxidising agent in specific chemical syntheses. It is also used in special-purpose fuels and as a nitrating agent, particularly in reactions where a controlled, low-temperature source of nitronium ions is required.
5. What does the Lewis structure of Dinitrogen Trioxide (N₂O₃) look like?
The Lewis structure of Dinitrogen Trioxide features a central N-N single bond. One nitrogen atom is double-bonded to an oxygen atom, while the other nitrogen atom is single-bonded to one oxygen and double-bonded to another. This arrangement results in formal charges on the atoms, and the molecule exhibits resonance, which contributes to its overall structure and properties within the p-block elements.
6. Why is Nitrogen Trioxide (N₂O₃) considered an unstable compound?
Nitrogen Trioxide's instability stems from the weak nitrogen-nitrogen (N-N) bond in its structure. This bond has a low dissociation energy, meaning it requires little energy to break. At temperatures above its boiling point (3.5°C), it readily decomposes back into its constituent gases, nitric oxide (NO) and nitrogen dioxide (NO₂). This decomposition is an equilibrium process that heavily favours the reactants at room temperature.
7. Is Dinitrogen Trioxide an ionic or covalent compound? Explain the bonding.
Dinitrogen Trioxide is a covalent compound. The bonding occurs between nitrogen and oxygen atoms, which are both non-metals. Instead of transferring electrons to form ions (ionic bonding), they share electrons to form covalent bonds and satisfy their valence shells. The molecule consists entirely of polar covalent bonds due to the difference in electronegativity between nitrogen and oxygen.
8. How does Nitrogen Trioxide act as an acid anhydride?
Nitrogen Trioxide acts as an acid anhydride because it reacts with water to form an acid. Specifically, when N₂O₃ reacts with water (H₂O), it forms nitrous acid (HNO₂). The balanced chemical equation for this reaction is: N₂O₃ + H₂O → 2HNO₂. This property is characteristic of many non-metal oxides.
9. What are the primary health and safety risks associated with Nitrogen Trioxide?
Handling Nitrogen Trioxide poses significant risks due to its nature. The main hazards are:
- High Toxicity: Inhaling its vapours can be fatal and severely damage the respiratory system.
- Corrosive Nature: Direct contact with the liquid can cause severe burns to the skin and eyes.
- Fire Hazard: It is a powerful oxidiser and does not burn itself but can cause combustible materials like paper, cloth, or oil to ignite or react explosively.
Strict safety measures, including protective gear and proper ventilation, are mandatory when working with this compound.
10. How does Nitrogen Trioxide (N₂O₃) differ from other common oxides of nitrogen like NO₂ or N₂O₅?
While all are oxides of nitrogen, they have key differences:
- Oxidation State: The oxidation state of nitrogen in N₂O₃ is +3, compared to +4 in NO₂ (Nitrogen Dioxide) and +5 in N₂O₅ (Dinitrogen Pentoxide).
- Physical State: N₂O₃ is a deep blue liquid/solid at low temperatures, whereas NO₂ is a brown gas and N₂O₅ is a white solid at room temperature.
- Corresponding Acid: N₂O₃ is the anhydride of nitrous acid (HNO₂), while N₂O₅ is the anhydride of nitric acid (HNO₃). NO₂ reacts with water to form both nitric and nitrous acids.
