Question

In a flame given by a candle complete combustion takes place in the outer most part and then in the middle part there is incomplete combustion but when oxygen is present everywhere then why is it that in one part there is complete combustion and in the other not?

Answer 1

The wax vapours are completely burnt in the outermost region. Complete combustion take place with the result of sufficient supply of Oxygen.

The blue zone at the bottom of the wick of a burning candle is due to burning of carbon-monoxide gas produce by the incomplete combustion of carbon particles in wax.

Whereas the non- luminous zone is the outermost zone of the flame where complete combustion of wax takes place. It is faintly blue in colour but hardly visible.