Differentiate between complete and incomplete combustion of a hydrocarbon and name a typical product of incomplete combustion.

Differentiate between complete and incomplete combustion of a hydrocarbon and name a typical product of incomplete combustion.

• A. Complete combustion yields CO and H2; incomplete yields CO2.
• B. Complete combustion yields CO2 and H2O; incomplete yields CO and/or C; a typical product of incomplete combustion is CO.
• C. Complete combustion yields CO2 and H2O; incomplete yields CO2.
• D. Complete combustion yields H2 and CO; incomplete yields H2O.

Answer: (B)

This question centers on what happens when a hydrocarbon burns with plenty of oxygen versus not enough. With enough oxygen, the fuel completely oxidises to stable end products: carbon dioxide and water, releasing energy in the process. If oxygen is limited, the carbon can’t fully oxidise, so products like carbon monoxide and even solid carbon (soot) can form; carbon monoxide is a common product of incomplete combustion. That’s why the correct description is: complete combustion yields carbon dioxide and water, while incomplete combustion yields carbon monoxide and/or carbon, with carbon monoxide being a typical product of incomplete combustion. The other possibilities would imply the wrong main products for complete or incomplete combustion.

This question centers on what happens when a hydrocarbon burns with plenty of oxygen versus not enough. With enough oxygen, the fuel completely oxidises to stable end products: carbon dioxide and water, releasing energy in the process. If oxygen is limited, the carbon can’t fully oxidise, so products like carbon monoxide and even solid carbon (soot) can form; carbon monoxide is a common product of incomplete combustion. That’s why the correct description is: complete combustion yields carbon dioxide and water, while incomplete combustion yields carbon monoxide and/or carbon, with carbon monoxide being a typical product of incomplete combustion. The other possibilities would imply the wrong main products for complete or incomplete combustion.