Question

why does candle burn with a yellow flame??

Answer 1

In a candle flame, we see that near the wick, the flame is nearly invisible and a yellow luminous zone surrounds this. Near the wick, the paraffin vapors are breaking down, releasing hydrogen and creating long, unsaturated carbon chains. This process is consumes heat and can only occur because of the heat supplied by the reactions occurring in the luminous region. Here, the carbon chains are very large and acting as tiny particles of soot. These soot particles burn just like charcoal, and the yellow light released by the candle flame is from these hot, burning soot particles.