What are the products of a complete combustion reaction?

• A. Carbon Dioxide and Water
• B. Carbon Monoxide and Water
• C. Oxygen and Water
• D. Nitrogen and Carbon Dioxide

Answer: (A)

In complete combustion, a fuel reacts with plenty of oxygen so that all the carbon becomes carbon dioxide and all the hydrogen becomes water. This is the clean, full-oxidation outcome for most fuels like hydrocarbons. So the products are carbon dioxide and water because the carbon atoms are fully oxidized to CO2 and the hydrogen atoms form H2O.

The other possibilities don’t fit complete combustion. Carbon monoxide would indicate incomplete combustion due to insufficient oxygen. Oxygen can’t be a product of combustion—it’s consumed as a reactant. Nitrogen isn’t produced from burning typical fuels in air; it mostly remains as nitrogen gas (N2) from the air, with only trace nitrogen oxides forming under very high temperatures—not as a standard product of complete combustion.