Chemistry
General Knowledge

Aluminium



Aluminium

Symbol : Al,
Atomic Number — 12,
Mass Number — 24

Physical and Chemical Properties :
Aluminium doesn’t occur in nature in free state but occurs in the forms of compounds like bauxite (A12O2.2H2O), Corundum (A12O3), Diaspore (A12O3.H20). Al is a white glazing metal like silver. This is a good conductor of heat and electricity, and it is malleable and ductile.

» Its melting point and boiling point are 659.8°C and 2,200°C

Uses :
This metal (aluminium) and its alloys are frequently used in aircrafts, motor vehicle industries. The cooking utensils are manufactured by the alloys of it and by the metal itself.

Alloys Composition
Aluminium bronze Al + Cu
Magnelium Al + Mg + Cu + Fe
Nickelloy Al + Ni + Cu
Duralium Mn + Mg

Compounds of Aluminium

Aluminium Chloride (AlC13) :
This is used as a catalyst in Friedel Craft reaction which occurs on an extensive level. This is also used as a catalyst in the production of Gasoline. It is also used in cracking of petroleum anhydrous A1C13.

Potash Alum [K2SO4.A1(SO4)3.24H2O] :
This is a double salt that appears as a colourless crystalline solid. This is also used in pulp-paper and leather industries, as an antiseptic and as a germicide after shaving, as a germicide for purification of water, etc.

Aluminium Hydroxide [Al(OH)3] :
This is a white amorphous powder insoluble in water, and it is a covalent compound. This is used in making fire proof and water proof clothes; in the name of aluminium gel, it is used as a drying agent, freshly precipitated A1(OH)3 absorbs colouring matter forming insoluble lakes.