Common Nitrogen Oxides: Properties, Preparation, and Uses
Nitrogen oxides are a mixture of nitrogen and oxygen-composed gases. Nitric oxide (NO) and nitrogen dioxide (NO2) are two of the most significant toxicologically important compounds. Other gases in this group are nitrogen monoxide (or N2O), and nitrogen pentoxide (NO5). A number of nitrogen oxides are formed by nitrogen reacting with oxygen.
It exhibits various oxidation states, ranging from +1 to +5 in its oxide forms. Nitrogen oxides having nitrogen in the higher state of oxidation are more acidic than those in the lower state of oxidation. Nitrogen dioxide is produced for the manufacturing process of nitric acid. Most nitric acid is used in fertiliser manufacturing, while some are used in explosives manufacturing for both military and mining uses. Let us find out more about the oxides of nitrogen in detail.
(Image will be uploaded soon)
Names of Oxides of Nitrogen
Let us now look at nitrogen oxide formula and about the different types of names of oxides of nitrogen: -
Dinitrogen Oxide
Dinitrogen oxide is a colourless, non-flammable gaseous compound. It has neutral properties. It's usually referred to as laughing gas. Dinitrogen oxide is formulated by the decomposition of ammonium nitrate at high temperatures.
NH4NO3 → 2H2O + N2O
Dinitrogen Trioxide
Dinitrogen trioxide is a deep blue, acidic solid. It can only be insoluble at low temperatures, i.e. in liquid and solid phases. As temperature rises, the equilibrium leads to the formation of the constituent gases. Dinitrogen trioxide is prepared by mixing equal parts of nitric oxide and nitrogen dioxide and by further cooling the mixture below −21 ° C.
NO + NO2 → N2O3
Nitrogen Monoxide
Nitrogen monoxide is a colourless gas. Its bond structure includes a valence electron, and it belongs to a class of diatomic molecules. Nitrogen monoxide is prepared by reducing the dilute nitric acid with copper.
3H2SO4 + 2NaNO2 + 2FeSO4 → 2NaHSO4 + Fe2(SO4)3 + 2H2O + 2NO
Nitrogen Dioxide
Nitrogen dioxide is a reddish-brown poisonous gas with a pungent smell and contributes greatly to air pollution all around the world. It is acidic in nature with a +4 nitrogen oxidation state. Nitrogen dioxide is formulated by the thermal decomposition of metal nitrate.
2Pb(NO3)2 → 4NO2 + 2PbO + O2
Dinitrogen Tetroxide
Dinitrogen tetroxide is a colourless solid that is in equilibrium with nitrogen dioxide. It is an efficient oxidising agent which is used as a solvent for the production of many chemical substances.
N2O4 ⇌ 2NO2
Dinitrogen Pentoxide
Dinitrogen pentoxide is a colourless solid. It undergoes sublimation marginally above room temperature. It is an erratic and potentially dangerous oxidising agent. It has been used as a solvent diluted in chloroform for nitration. Dinitrogen pentoxide is produced by the process of dehydration of nitric acid (HNO3) with phosphorus (V) oxide.
Solved Questions on Nitrogen Oxide
1. What are the Industry and Natural Sources for the Emission of Oxides of Nitrogen?
The industry sources of nitrogen include oil and gas extraction, the supply of electricity, mining, manufacturing industries and petroleum manufacturing.
The natural sources for the emission of nitrogen include: Biological nitrogen recycling involves processes that produce nitric oxide and nitrous oxide as intermediates. Thermal processes in the atmosphere which take place during lightning or wildfires also produce nitrogen oxides.
2. What are the Ways to Reduce Nitrogen Oxide Emissions to Treat the Pollution of Air?
The ways to reduce the emission of nitrogen oxide are:
Using a limited quantity of nitrogen fertilisers
Using catalytic converters in cars to reduce emissions
It can be done in two ways:
Reduction: Removal of oxygen from the nitrogen oxide
Oxidation: Adding oxygen to carbon monoxide to form carbon dioxide, which is less harmful than carbon monoxide.
3. What are some Applications of Nitrous Oxide?
Some applications of Nitrous Oxides are:
Used for sedation in dentistry
Used as analgesic to control pain
It is extremely safe does not react with body fluids
Decreases anxiety
Rapid and onset recovery
Conclusion
This is the explanation of all the oxides of nitrogen and their formulas. Focus on the formula and chemical properties of all these nitrogen oxides and understand their differences. Learn these oxides separately to understand their features properly.
FAQs on Oxides of Nitrogen: Types, Chemical Formulas & Examples
1. What are the common oxides of nitrogen and their chemical formulas?
Nitrogen forms several oxides due to its ability to exhibit a wide range of oxidation states. The common oxides of nitrogen as per the CBSE syllabus are:
Dinitrogen Oxide (Nitrous Oxide): N₂O
Nitrogen Monoxide (Nitric Oxide): NO
Dinitrogen Trioxide: N₂O₃
Nitrogen Dioxide: NO₂
Dinitrogen Tetroxide: N₂O₄
Dinitrogen Pentoxide: N₂O₅
2. How are the different oxides of nitrogen prepared?
The preparation methods for the main oxides of nitrogen vary based on the desired compound:
N₂O (Nitrous Oxide): Prepared by gently heating ammonium nitrate.
NH₄NO₃ → N₂O + 2H₂ONO (Nitric Oxide): Prepared by the reaction of sodium nitrite with ferrous sulphate and sulphuric acid.
2NaNO₂ + 2FeSO₄ + 3H₂SO₄ → Fe₂(SO₄)₃ + 2NaHSO₄ + 2H₂O + 2NON₂O₃ (Dinitrogen Trioxide): Prepared by mixing equal parts of NO and NO₂ and cooling the mixture to below -20°C.
NO + NO₂ ⇌ N₂O₃NO₂ (Nitrogen Dioxide): Prepared by heating lead nitrate.
2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂N₂O₅ (Dinitrogen Pentoxide): Prepared by dehydrating nitric acid (HNO₃) with phosphorus pentoxide (P₄O₁₀).
4HNO₃ + P₄O₁₀ → 4HPO₃ + 2N₂O₅
3. What are the structures and oxidation states of nitrogen in its various oxides?
The structure and oxidation state of nitrogen are crucial to understanding the properties of its oxides. Here is a summary:
N₂O (+1): A linear, unsymmetrical molecule (N-N-O).
NO (+2): A linear molecule with an odd number of electrons, making it paramagnetic.
N₂O₃ (+3): A planar molecule with an N-N bond, existing as an unsymmetrical O₂N-NO structure.
NO₂ (+4): An angular or bent molecule with an odd electron, which gives it a brown colour and paramagnetic nature. The hybridization of NO₂ is sp².
N₂O₄ (+4): Exists in equilibrium with NO₂; it is the dimer form, which is planar with an N-N bond and is diamagnetic.
N₂O₅ (+5): A planar molecule in the gaseous state, but exists as the ionic solid [NO₂]⁺[NO₃]⁻ in its solid state.
4. Why do nitrogen oxides show both acidic and neutral characteristics?
The chemical nature of nitrogen oxides is directly linked to the oxidation state of the nitrogen atom. As the oxidation state of nitrogen increases, the acidic character of the oxide also increases.
Neutral Oxides: Dinitrogen oxide (N₂O) and nitrogen monoxide (NO) have low oxidation states (+1 and +2, respectively). In these states, they do not react with water to form acids and are therefore considered neutral.
Acidic Oxides: Oxides like N₂O₃, NO₂, N₂O₄, and N₂O₅ have higher oxidation states (+3, +4, and +5). These oxides react with water to form oxyacids (e.g., nitrous acid, nitric acid) and are thus classified as acidic oxides.
5. How do oxides of nitrogen contribute to environmental issues like acid rain and smog?
Oxides of nitrogen, collectively known as NOₓ (mainly NO and NO₂), are significant air pollutants.
Acid Rain: In the atmosphere, nitrogen dioxide (NO₂) reacts with water and oxygen to form nitric acid (HNO₃). This nitric acid dissolves in rainwater, making it acidic. This phenomenon is known as acid rain, which damages buildings, harms aquatic life, and affects soil quality.
Photochemical Smog: Nitrogen oxides are key components in the formation of photochemical smog. Sunlight breaks down NO₂ into NO and a free oxygen atom. This highly reactive oxygen atom then combines with atmospheric oxygen (O₂) to form ozone (O₃). This ground-level ozone, along with other pollutants, creates the hazy, harmful mixture known as smog.
6. What is the difference between nitrous oxide (N₂O) and nitrogen dioxide (NO₂)?
Students often confuse nitrous oxide and nitrogen dioxide, but they are very different compounds:
Chemical Formula & Name: Nitrous oxide is N₂O (also called dinitrogen monoxide). Nitrogen dioxide is NO₂.
Oxidation State: In N₂O, nitrogen has an oxidation state of +1. In NO₂, it has an oxidation state of +4.
Properties: Nitrous oxide is a colourless, relatively unreactive gas, famously known as "laughing gas". Nitrogen dioxide is a highly reactive, toxic gas with a characteristic reddish-brown colour.
Nature: N₂O is a neutral oxide, while NO₂ is an acidic oxide.
7. Why does nitrogen dioxide (NO₂) tend to dimerise?
Nitrogen dioxide (NO₂) dimerises to form dinitrogen tetroxide (N₂O₄) because the NO₂ molecule contains an odd number of valence electrons. This makes it an odd-electron species, which is highly reactive and unstable. To achieve stability, two NO₂ molecules pair up their unpaired electrons to form a covalent N-N bond, resulting in the stable, diamagnetic N₂O₄ molecule.
This is a reversible reaction, represented as: 2NO₂ (brown, paramagnetic) ⇌ N₂O₄ (colourless, diamagnetic). The equilibrium is temperature-dependent; lower temperatures favour the formation of stable N₂O₄.
8. What are the primary health effects associated with exposure to nitrogen oxides?
Exposure to high concentrations of nitrogen oxides (NOₓ) can have serious health consequences. The primary effects include:
Respiratory Issues: Low-level exposure can cause irritation to the eyes, nose, throat, and lungs, leading to coughing, shortness of breath, and an increased risk of respiratory infections like pneumonia and bronchitis.
Lung Damage: High levels of exposure can cause severe damage to lung tissue, leading to pulmonary edema (fluid build-up in the lungs), which can be fatal.
Aggravation of Existing Conditions: For individuals with asthma, exposure to NO₂ can worsen their symptoms and increase the frequency of attacks.
