Write the chemical equation for this reaction? and explain?

Question

Since combustion results in the production of carbon dioxide gas (Co2) and water vapor. explain the production of the black solid (Carbon) found on a test tube when held against a luminous ( yellow) flame. Write the chemical equation for this reaction?

Answer 1

The reason for the soot is that if there is not a large enough supply of oxygen, the carbon is not completely oxidised to CO2. So less heat is released and only a yellow flame instead of a blue flame is produced.

Assuming you're source is CH4,

CH4 + O2 -> C + 2H2O