What is Aluminium Oxide (Al2O3)?

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It is found naturally as corundum, Ruby’s, sapphires, and emeralds. It is an amphoteric substance, which reacts with both acids and bases. It occurs as solid and appears white. It is odourless and insoluble in water. The most common occurrence of this compound is in crystalline form, called α-aluminium oxide or corundum. Due to its hardness, is widely used and suitable to use as an abrasive and in cutting tools.

Aluminium oxide Structure

(Al2O3 Structure)

Properties of Aluminium oxide - Al2O3

Chemical Properties of Aluminium Oxide

1. Reaction with sodium hydroxide

Aluminium oxide reacts with sodium hydroxide to produce sodium aluminate and water. This reaction takes place at a temperature of 900-1100°C. Salt and water are obtained in this reaction in which aluminium oxide acts as an acid.Al2O3 + 2NaOH → 2NaAlO2 + H2O

2. Reaction with sulphuric acid

Metal oxides are generally basic in nature but aluminium oxide is amphoteric oxide.Hence it acts both as acid and base. In this case, it acts as a baseAl2O3 + H2SO4 → Al2(SO4)3 + H2OThis is a neutralisation reaction.

3. Reaction with hydrochloric acid

Aluminium oxide contains oxide ions, and thus reacts with acids in the same way sodium or magnesium oxides do. Aluminium oxide reacts with hot dilute hydrochloric acid to give aluminium chloride solution.Al2O3+6HCl → 2AlCl3+3H2O

Aluminium oxide (Al2O3 ) Uses

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