NATE Gas Heating Practice Exam

What type of gas is produced as a result of incomplete combustion?

1. Carbon dioxide

2. Nitrogen oxide

3. Carbon monoxide

4. Hydrogen

The correct answer is: Carbon monoxide

Incomplete combustion occurs when there is insufficient oxygen available to completely convert fuel into carbon dioxide and water. During this process, one of the primary byproducts formed is carbon monoxide, a colorless and odorless gas that can be harmful or even fatal in high concentrations. Carbon monoxide is created instead of carbon dioxide due to the limited supply of oxygen, leading to a situation where carbon in the fuel is only partially oxidized. Understanding this process is crucial for ensuring safety in environments where combustion occurs, such as in heating systems or gas appliances, as carbon monoxide can build up to dangerous levels, particularly in poorly ventilated areas. The other gases mentioned, such as carbon dioxide and nitrogen oxide, are typically products of complete combustion or other chemical reactions rather than resulting from incomplete combustion.