*Gas used in LPG - Butane, Propane

*Strong smelling substance added to LPG - Ethyl Mercaptan or Ethanethiol

*Tear Gas - Ammonia (NH3)

*Gas with foul smell - Hydrogen Sulphide (H2S)

*Laughing gas - Nitrous Oxide (N2O)

*Gas used in refrigeration - Freon is chemically Dichloro Diflouro Methane

*Gobar gas is a mixture of - Methane, CO2 and hydrogen

*Gas mixed with oxygen and given to patients with restricted breathing- Helium

*A major air pollutant, the percentage presence of which is checked in vehicle pollution test - Carbon monoxide

*The gas which is responsible for the formation of brown air in traffic congested cities - Nitrogen oxide

*Major gaseous pollutant of areas located near thermal power station - Suphur dioxide

*Natural gas - Mainly methane with small quantities of ethane and propane

*Gases responsible for depletion of ozone layer - Chloroflouro carbons

*Gas used in gas welding and also artificial ripening of fruits - Acetylene

*Gas used in electric bulbs - Argon

*Gas used in flourescent lamps - Mercury vapour

*Gas known as marsh gas - Methane

*Gas responsible for acid rain - Sulphur dioxide

*Gas most abundant in earth's atmosphere- Nitrogen (78%) , oxygen 21% (appx)