why does LPG gas stove produce blue flame not yellow flame?

Answer 1

Complete combustion occurs.

Answer 2

Alright consider a Bunsen Burner. When the hole is open it allows enough oxygen through and so therefore allows the hydrocarbon compound from the source to undergo complete combustion releasing carbon dioxide and water in the form of water vapour as the main by products. When you close the hole not enough oxygen can enter and so therefore incomplete combustion takes place.

Same case here, the gas stove produces blue flame because enough oxygen is available and so therefore complete combustion process takes place instead of incomplete combustion producing blue flame instead of yellow flame.

Answer 3

The yellow flame of a candle is caused by the glowing carbon that is not completely combusted, due to relatively low combustion temperature and long chains of the wax.

For the blue flame "the blue color arises specifically due to emission of excited molecular radicals in the flame"
http://en.wikipedia.org/wiki/Flame

Answer 4

Because it has enough oxygen to achieve complete combustion. Yellow flames result from incomplete combustion of fuel. Yellow flames are colder than blue flames.

Answer 5

Food spillage on the burners reduces air intake for the burners that causes the flame to burn yellow and that is a cold flame Food will take longer to cook and therefor cost more in gas to cook. That in turn then produces soot and the fatal gas carbon monoxide, and if bad enough you will not have to bother about cooking the Crem. will do it for you. Clean you cooker.