why aromatic compound give sooty flam on burning time?

In Aromatic compounds the carbon-hydrogen ratio is high. Theyburnwith asooty yellowflamebecause of the high carbon-hydrogen ratio.A flame is "sootier" when there is less oxygen present in it. In an alkane you have more hydrogen to burn than carbon and 2 hydrogen atoms only require one oxygen to burn. Since CO2 is produced when burning organic compounds one C requires 2 oxygen atoms in order to burn.So when you have more carbons per hydrogens burning, you get a larger consumption of oxygen and less oxygen means sootier flame.