General Knowledge



» It is a mixture of gases produced during decay of biomass in the absence of oxygen.
» Methane (75%) is the main constituent of biogas.
» It is an excellent fuel and burns without producing smoke.

Ethylene (CH2 = CH2)

It is used as an anaesthetic for the preservation and artificial ripening of green fruits and also used in the manufacturing of ethyl alcohol, ethylene glycol, polythene, and polyvinyl chloride (PVC).

Acetylene (CH = CH)

A colourless gas with sweet smell. The characteristic odour associated with acetylene is due to phosphine present as an impurity. It is dangerously explosive in liquid state, so its use or storage is prohibited by law.

Benzene (C6H6)

It is the simplest aromatic hydrocarbon. It was discovered by Faraday in 1825. He obtained it by the destructive distillation of whale oil. It is used as a solvent for fats, resins, etc. in dry-cleaning, and it is also used as a motor fuel under the name benzol.

Toluene (C6H5CH3)

It was first obtained by the dry distillation of Tolu Balsam. It is used as a commercial solvent in the manufacturing of explosive (TNT), drugs (chloramine-T) and dyestuffs. It finds use in the manufacturing of saccharin and printing inks. With petrol and benzene, toluene is used as an antifreeze.

Xylene (C8H10)

It is used in the manufacturing of lacquers and as solvents for rubber.

Naphthalene (C10Hg)

It constitutes about 6-10% of coal tar. It is colourless crystalline solid with strong characteristic odour. It is used for preventing moths in clothes, as an insecticide and in the manufacturing of azodyes, eosin, and indigo.