What are the byproducts of complete combustion?

The byproducts of complete combustion primarily include carbon dioxide, water vapor, and nitrogen. During complete combustion, a hydrocarbon fuel reacts with oxygen to produce energy, and ideally, all the carbon is fully oxidized to carbon dioxide. Water vapor is formed when the hydrogen in the fuel combines with oxygen as well.

Nitrogen, while not a product of the combustion itself, is present in the air and is not consumed in the reaction but is instead a non-reactive bystander in this process. Therefore, in the context of combustion, the presence of nitrogen is often noted, but it does not participate in the combustion reaction.

This is why carbon dioxide and water vapor are the primary byproducts you would expect from complete combustion, and the inclusion of nitrogen reflects its presence in the environment. The other options include gases that either do not form in complete combustion (like carbon monoxide or sulfur dioxide) or irrelevant compounds that are not typically significant byproducts of the complete combustion process.