Use adaptive quiz-based learning to study this topic faster and more effectively.

# Complete and incomplete combustion of alkanes

Complete combustion occurs when there is sufficient or excess oxygen present.

There must be enough oxygen atoms to convert all of the alkanes into the products of the reaction: carbon dioxide $(\ce{CO2})$ and water $(\ce{H2O})$.

The complete combustion of methane has the equation: $$\ce{CH4 + 2O2 -> CO2 + 2H2O}$$

Incomplete combustion occurs when there is insufficient oxygen. Such a combustion produces soot (carbon particles) and carbon monoxide $(\ce{CO})$ (in addition to water) instead of carbon dioxide.

The incomplete combustion of methane involves two different reactions: $$\ce{2CH4 + 3O2 -> 2CO + 4H2O}$$ $$\ce{CH4 + O2 -> C + 2H2O}$$

Carbon monoxide is a very poisonous gas.