Why are There Different Colors in Bunsen Burner Flames?

why does the orange colored flame from a bunsen burner turns bluish when air is admitted and why isn't there a black smoke emitted while the orange flame has?
- blesmee (age 16)
san fernando city, la union, philippines

  Hello Blesmee,

It is mainly due to different ratios of oxygen to the combustable gas.  An excellent source of information on the subject can be found at .   The following picture and explanation is taken from this article:

                              

Different flame types of a depend on oxygen supply. On the left a rich fuel with no premixed oxygen produces a yellow sooty diffusion flame; on the right a lean fully oxygen premixed flame produces no soot and the flame color is produced by molecular radicals, especially CH and C2 .

 

LeeH

(published on 07/06/2014)