Why does the soot only appear where the flame is present?Updated 18 days ago

All of the free carbon chains are consumed by the heat, a blue flame (relatively speaking) lacks color. Only water vapor and carbon dioxide are produced by this kind of fire. Period. On the other hand, when we burn isopropyl alcohol in our tiny fireplace, we make carbon dioxide, water vapor, and loose carbon chains. The fact that isopropyl alcohol is still a full combustion, however, is significant. Therefore, under the heat of the fire, all of those carbon chains are burned away. This is why an isopropyl alcohol flame looks yellow; those are the blazing embers of carbon that are being consumed. Thus, carbon, or what we refer to as soot, will settle wherever the flame comes into contact. However, it won't be able to escape the scorching flame's umbrella. Of course, this assumes there is a sufficient amount of oxygen present to permit complete burning.