Which of the following is a byproduct of combustion?

Combustion is a chemical reaction that typically occurs when a fuel combines with oxygen, leading to the release of energy. This process results in various byproducts depending on the composition of the fuel and the completeness of the combustion.

Carbon monoxide is indeed one of the byproducts of combustion, particularly when there is insufficient oxygen for complete combustion to occur. In such cases, carbon in the fuel is partially oxidized to form carbon monoxide (a toxic gas), rather than being fully oxidized to carbon dioxide. This makes carbon monoxide a common and dangerous byproduct in scenarios such as vehicle exhaust, poorly vented gas appliances, or in any situation where combustion is not occurring efficiently.

While carbon dioxide is also a byproduct of combustion—formed during complete combustion when enough oxygen is present—carbon monoxide is significant due to its health risks and prevalence in incomplete combustion scenarios. Ozone, on the other hand, does not form directly as a byproduct of combustion in the same way, and hydrogen is typically not a product of combustion processes involving hydrocarbons. Understanding the implications of these byproducts is crucial for evaluating air quality and the safety of combustion systems.