Uses of Boron
1) Boron fibres have enormous tensile strength and hence are used to make bullet proof vests and light composite material for aircraft.
2) Natural boron is 20% boron-10 and 80% boron-11.Boron-10 has a high cross section for absorption of low energy neutrons.
3) Borax and boric acid are used in the manufacture of heat resistant glass, glass wool and fiber glass. Borax is also used as a flux in soldering ,as a constituent of medicinal soaps due to its antiseptic properties ,in the manufacture of enamels and glazes for earthenwares i.e. tiles, pottery etc. An aqueous solution of orthoboric acid is also used as a mild antiseptic.
4) It is used in steel industry for increasing the hardness of Steel. In fact boron has replaced expensive metals like Mo, Cr and W in with manufacture of special hard steels.
5) Boron compounds are being used as rocket fuel because of high energy/ mass ratio.
Uses of aluminium
Aluminium is a bright silvery white metal with high tensile strength.
1) It is used for making transmission cables and for winding the moving coils of dynamos or motors.
2) It is used for making aluminium paint for protection of iron and zinc. Aluminium powder mixed with linseed oil shines like silver and hence is called silver paint.
3) Aluminium is a cheap metal which resist corrosion. Therefore ,it is used for making household utensils ,cans for drinks, tubes for toothpaste, pictures frames, trays etc. It is also used in building for making angles for doors, windows.
4) Aluminium foil is used for wrapping fine articles like photographic films , pharmaceutical products ,cigarettes sweets.
5) Aluminium powder is used as a reducing agent in aluminothermic process for extraction of chromium and manganese from their ores.
6) Aluminium powder is used in flash light bulbs for indoor photography.
7) Large amount of aluminium are converted into alloys.Some important alloys of aluminium are Aluminium bronze (used in coins, utensils, jewellery, picture frame), Magnalium (used in light instruments, balance beams, pressure cookers) , duralumin (used in automobile parts, pressure cooker)
8) Al(OH)3 is widely used as an antacid for treatment of digestion.
9) Anhydrous AlCl3 is used as a catalyst in Friedel – Crafts reaction and in cracking of petroleum.Hydrated AlCl3 is used as a mordant in dyeing.
10) Potash alum is used for purification of water, as styptic for stopping bleeding , in form type fire extinguisher, as mordant for dyeing and for tanning of leather and sizing of paper.