Technical Standards and Safety Authority (TSSA) G3 Practice Exam

Carbon monoxide is a product of the incomplete combustion of which substance?

1. Nitrogen

2. Oxygen

3. A hydrocarbon

4. An inorganic compound

The correct answer is: A hydrocarbon

The generation of carbon monoxide occurs as a result of the incomplete combustion of hydrocarbons. When hydrocarbons, which are compounds consisting primarily of hydrogen and carbon, undergo combustion in conditions where there is insufficient oxygen, they do not fully oxidize into carbon dioxide and water. Instead, they can form carbon monoxide (CO) along with other byproducts. The critical factor is that hydrocarbons, like natural gas, propane, or gasoline, contain carbon atoms that play a significant role in combustion reactions. If the combustion process is not optimal or oxygen supply is limited, the hydrocarbons cannot completely convert into carbon dioxide, leading to the formation of carbon monoxide, which is a colorless and toxic gas. Comparatively, nitrogen and oxygen do not form carbon monoxide under combustion conditions; they are rather constituents of the air or reactants that facilitate the combustion process. Inorganic compounds may have various combustion characteristics, but it is the hydrocarbons specifically that are directly associated with carbon monoxide production during incomplete combustion scenarios. Thus, hydrocarbons are clearly identified as the source of carbon monoxide in these processes.