A chemical oxide of aluminium and oxygen, aluminium oxide is also known as alumina or aloxide. It is basically an odourless, white amorphous material that is amphoteric in nature. Aluminium oxide finds its place in various industrial, commercial and chemical enterprises. It is also present in some essential naturally occurring minerals like Bauxite and Corundum of which corundum is a naturally occurring crystalline form of aluminium oxide which is most commonly found to be in use.
Properties of Aluminium Oxide
The symbol of aluminium oxide is given as - Al2O3. Its molar mass is denoted as 101.96 g/mol. Its boiling point is presented at 2977 degrees celsius and its melting point is presented at 2072 degrees celsius. Its density is 3.95 g/cm3.
Chemical Formula of Aluminium Oxide
Aluminium oxide is an ionic compound. Its formula is written as Al2O3 which tells us that it has aluminium atoms with +3 charge and oxygen atoms with -2 charge. Now, what does this mean? In this chemical process, aluminium loses three electrons whereas oxygen gains two electrons. This is how we derive the chemical formula for aluminium oxide.
Structure of Aluminium Oxide
The structure of aluminium oxide is formed when two aluminium atoms bond with two oxygen atoms each, which means it has three oxygen atoms.
How do we Derive Equations of Aluminium Oxide?
As we have seen earlier, aluminium oxide is amphoteric by nature. Now we also call amphoteric oxides metal oxides because they can form reactions with both acids as well as bases to produce salt and water. Zinc Oxide (ZnO), SnO and PbO are other common examples of amphoteric or metallic oxides.
Following are the chemical properties or chemical reactions of Aluminium Oxide -
When Aluminium Oxide reacts with hot and dilute hydrochloric acid, it gives aluminium chloride solution and water as its products. We must bear in mind that sodium and magnesium oxides also produce similar reactions because all three of them contain oxide ions. Here Aluminium oxide acts as a base.
Al2O3 + 6HCl → 2AICl3 + 3H2O
When aluminium oxide reacts with sodium hydroxide at a temperature of 900-1100 degrees celsius, it gives sodium aluminate and water as its products. In this reaction, aluminium oxide behaves like an acid. The reaction is as follows -
Al(OH)3 + NaOH → NaAlO2 + 2H2O
In a neutralisation reaction, aluminium oxide reacts with sulphuric acid to produce aluminium sulphate and water. Here aluminium oxide acts as a base.
Al2O3 + H2SO4 -> Al2 (SO4) 3 + H2O.
Various Uses of Aluminium Oxide
As a popular and commonly found metallic oxide, aluminium oxide has the following uses -
In the Claus process, it is used as a catalyst
It is used to dehydrate alcohols to alkenes
It can be used as a purificatory material to separate water from a gas stream
It finds its place in paints, making spark plug insulators and in cosmetic industries.
In chromatography, it is used as a medium
Aluminium oxide is strong yet light in weight. Hence it is used regularly to create body armours and in bulletproof windows. It also finds applications in the medical industry.
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FAQs on Aluminium Oxide Formula
1. Write Some Properties of Aluminium Oxide.
Some properties of Aluminium oxides are:
- It is an Electrical insulator with High thermal conductivity and low density.
- Wear and corrosion resistant, due to its strength and lightweight it is suitable for preparing body armors, and bulletproof windows.
- High compression strength and stiffness.
- Chemical and thermal stability, high melting and boiling point.
2. Aluminium Oxide is Acidic or Basic in Nature?
Aluminum oxide is acidic and basic in nature. This type of oxide is known as amphoteric oxides, the balanced equation for aluminum oxide is shown below.
Al2O3 + 6HF → 2AIF3 + 3H2O
Al2O3 + 2NaOH + 3H2O → 2NaAl(OH)4
3. Aluminium Oxide is Soluble in Water?
Aluminum oxide has high lattice energy and low heat of hydration and is not soluble in water.