Final answer:
Carbon monoxide (CO) is the most common product in structure fires due to incomplete combustion in oxygen-limited conditions. It is a toxic gas and poses significant health risks in confined spaces. CO is produced alongside carbon dioxide, water, and thermal energy, with carbon monoxide being prevalent when insufficient oxygen is available.
Step-by-step explanation:
The most common product in structure fires is carbon monoxide (CO). Combustion in such fires often occurs in conditions that are not ideal, leading to incomplete combustion where oxygen supply is limited. This results in the production of carbon monoxide alongside carbon dioxide (CO₂), water (H₂O), and thermal energy. Carbon dioxide is a complete combustion product when there is sufficient oxygen, but carbon monoxide, an incomplete combustion product, is more prevalent in structure fires. Particularly, carbon monoxide is known for being a very toxic gas that can lead to fatalities if inhaled in confined, unventilated spaces.
Hydrocarbons such as methane (CH₄) and propane (C₃H₈) are frequently used in combustion processes. When combusted fully, they produce carbon dioxide and water; however, as seen in the reaction 2CH₄ + 3O₂ → 2CO + 4H₂O, when not enough oxygen is present, carbon monoxide and water are produced instead. This reaction signifies the formation of carbon monoxide in a limited oxygen environment.
The Lewis structures of CO and CO₂ reveal that CO has a triple bond and one lone pair of electrons on the carbon atom, while CO₂ shows one carbon atom double-bonded to two oxygen atoms, with no lone pairs on the carbon atom