Liquefied Petroleum Gas ( LPG) is  a mixture of propane and butane in varying percentages . Propane and Butane are basically alkanes owing to which they do not react with each other chemically to from a third compound but co exist together as a finely distributed mixture with each having its own distinct properties.

As the characteristics of any good grade LPG depends upon the percentages of Propane and Butane present in the mixture so care should be taken to ensure that the LPG being used has higher percentage of Propane and is totally free from unsaturated. For use in packed containers Indian standards have a maximum permissible percentage of propane as 50 %