Dioxygen

Oxygen is a member of the chalcogen group of the periodic table, a highly reactive nonmetal that rapidly forms oxides with the majority of elements and other compounds. Oxygen is the most plentiful element on Earth and, after hydrogen and helium, the third most abundant element in the universe. Diatomic oxygen makes up 20.95 percent of the Earth’s atmosphere nowadays. Oxygen is found in about half of the Earth’s crust in the form of oxides.

Oxygen is a chemical element with the symbol O and the atomic number 8.

Dioxygen

Dioxygen, with the chemical formula O2, is one of the most prevalent allotropes of elemental oxygen. While it is frequently referred to as oxygen, it is also referred to as molecular oxygen, dioxygen or oxygen gas to distinguish it from elemental oxygen.

Except for noble gases, oxygen gas reacts with nearly every element. Oxides are the resultant compounds. While oxygen gas is not flammable on its own, it is necessary for combustion. Additionally, it is a life-sustaining gas, as mammals require oxygen to survive, and it assists in the release of energy.

Physical Properties of Dioxygen

• It is a colourless, odourless, and tasteless gas.

• It is denser than air, weighing 1.429 g/L.

• It is mildly soluble in water, barely enough for aquatic life to survive.

• Oxygen has a melting point of around 54.36 degrees Kelvin and a boiling point of roughly 90.188 degrees Kelvin.

• Oxygen can exist in any of the three states: solid, liquid, or gas, depending on the temperature and pressure.

Chemical Properties of Dioxygen

• It is paramagnetic.

• Normally, oxygen is inert when it comes into contact with acids and bases.

• Due to the fact that oxygen is an excellent oxidant, it aids in combustion.                 

Fuel + O2 ⟶ CO2 + H2O

• It interacts directly with nearly all metals and nonmetals to generate their oxides.

4Na + O2 → 2Na2O (With Metal)

C + O2 → CO2 (With Non-metal)

• Rust is formed on iron when oxygen and moisture combine.

Fe + O2 + H2O ⟶ Fe2O3.nH2O (Hydrated Iron Oxide)

Laboratory Preparation of Dioxygen

Dioxygen can be made in a variety of ways in the laboratory.

• Dioxygen is produced during the catalytic breakdown of Sodium Potassium Chlorate with Magnesium dioxide. When heated to 420K in the presence of MnO2, this reaction occurs.

2KClO3 → 2KCl + 3O2

• Dioxygen is produced during the thermal breakdown of metal oxides with a low electrode potential in the electrochemical series, such as Mercury and Silver oxides.

2HgO (s) → 2Hg (l) + O2 (g)

2PbO2 (s) → 2PbO (s) + O2 (g)

• Dioxygen is formed through the thermal decomposition of oxygen-rich salts such as nitrates and permanganates.

2KNO3 → 2KNO2+ O2

2KMnO4 → K2MnO4 + MnO2 + O2

2NaNO3 → 2NaNO2 + O2

• Preparation of Dioxygen from hydrogen peroxide

Oxygen can be synthesised from hydrogen peroxide, which slowly decomposes into water and oxygen. A catalyst, manganese (IV) oxide, can be used to accelerate the process. When manganese (IV) oxide is combined with hydrogen peroxide, oxygen bubbles are produced.

2H2O2(aq) → 2H2O(l) + O2(g)

• Preparation of oxygen from oxides

2Ag2O → 4Ag+ O2

2BaO2→2BaO+O2

3MnO2 → Mn3O4 +O2

2PbO4 → 2PbO + 3O2

2MnO2 + 2H2SO4 → 2MnSO4 + 2H2O + O2

• Fractional distillation of liquid air to produce oxygen

Through the liquefaction and fractional distillation of air, it is possible to get oxygen from the atmosphere. Liquid air is a mixture of liquid nitrogen with a boiling point of 196 degrees Celsius and liquid oxygen with a boiling point (183o C). Because nitrogen is more volatile (i.e., has a lower boiling point), it is the first to boil away, leaving just pure oxygen remaining.

Industrial Production of Dioxygen

When it comes to industrially manufacturing dioxygen from air, there are two basic approaches to consider.

The gaseous nitrogen (N2) separates from the liquid oxygen (O2) during a fractional distillation of liquefied air. A mixture of liquid Nitrogen and liquid Oxygen constitutes liquid air in this instance. Nitrogen is more volatile than other elements because of its lower boiling point. It boils first, releasing just pure oxygen into the atmosphere.

It is also possible to flow clean, dry air through one bed of a pair of zeolite molecular sieves, which absorbs the N2 gas and gives the gas, which is 90-93 percent oxygen, as a second technique.

Uses of Dioxygen

• It is necessary for respiration to have dioxygen present.

• It is present in oxygen cylinders that are used in hospitals and climbing expeditions, among other places.

• It is used to weld and cut metals in the form of oxy-acetylene, which is a type of gas.

• Oxygen gas interacts with acetylene gas to generate an oxy-acetylene flame. This flame may be used to cut and weld metals because of its high melting point.

• It is used in the production of liquid rocket fuel.

• Nitrogen dioxide is utilised in the production of nitric acid.

• It is used in artificial respiration in combination with carbon dioxide or methane to create a more oxygenated environment.

• The process of laser cutting requires use of oxygen.

• The element oxygen is utilised in combustion processes. Materials that do not ordinarily burn in air burn easily when exposed to oxygen, and so the combination of oxygen and air enhances combustion.

• It is necessary to use oxygen in water treatment operations such as wastewater purification and sewage treatment.

Conclusion

Dioxygen is a critical chemical for human life since it is engaged in critical biological processes such as cellular respiration and the manufacture of a range of biological compounds, including hormones, as well as defensive systems. As a result, molecular oxygen is required in the majority of the human body’s tissues. The body’s metalloenzymes and proteins transport molecular oxygen from the lungs to the source of need. Other metalloenzymes then use molecular oxygen attached to a transition metal core to biotransform molecules with activities ranging from biodegradation to biosynthesis. Due to the fact that these enzymes occur in a variety of shapes and forms, they are extremely adaptable and efficient. Unsurprisingly, they are of considerable interest to the biotechnology industry, where their potential for biosynthesis of medications and fine chemicals is being explored.