What are the products of complete combustion?

Complete combustion occurs when a hydrocarbon reacts fully with oxygen, resulting in the highest level of oxidation of the carbon and hydrogen found in the fuel. The primary products of this reaction are carbon dioxide (CO2) and water (H2O).

When a fuel is burned completely, the carbon in the fuel combines with oxygen to form carbon dioxide. At the same time, hydrogen from the fuel reacts with oxygen to form water. This efficient reaction means that all available carbon and hydrogen are converted to these stable products, assuming there is an ample supply of oxygen.

Additionally, sulfur dioxide (SO2) may be produced if sulfur is present in the fuel; however, it is not a product of the combustion of hydrocarbons themselves but results from burning fuels that contain sulfur. Therefore, while sulfur dioxide can be a byproduct in real-world scenarios, it is not a product of complete combustion solely defined by hydrocarbons.

The choice indicating carbon dioxide, water, and sulfur dioxide captures the primary products of hydrocarbons with the additional acknowledgment that SO2 can be produced from fuels that contain sulfur. This aligns with the concept of complete combustion, distinguishing it from partial combustion that might yield carbon monoxide (CO) or other compounds when oxygen is limited.