How are oxides of nitrogen formed during the combustion of fuels?

Oxides of nitrogen are primarily formed during the combustion of fuels due to the high temperatures present in car engines. When combustion occurs at elevated temperatures, nitrogen gas (which makes up about 78% of the Earth's atmosphere) can react with oxygen to form nitrogen oxides (NO and NO2). This process is common in internal combustion engines, where temperatures can reach enough to facilitate such reactions.

The formation of nitrogen oxides is particularly significant because they contribute to air pollution and can lead to the formation of smog and acid rain. The reaction generally occurs at temperatures above 1,200 degrees Celsius, which is typical in engine combustion, demonstrating the correlation between high temperatures and the production of these gases.

Thus, the main mechanism responsible for the formation of oxides of nitrogen during fuel combustion is the reaction of nitrogen with oxygen at these high temperatures, making the correct answer related to how this high-temperature environment facilitates the formation of nitrogen oxides.