In comparison to natural gas, propane requires more _________.

The correct answer is that propane requires more air compared to natural gas. This is primarily due to the differences in the chemical composition and combustion characteristics of the two fuels.

Propane (C3H8) has a higher carbon-to-hydrogen ratio than natural gas, which is primarily methane (CH4). As a result, propane needs a greater volume of air to achieve a complete combustion process. The stoichiometric air-fuel ratios, which indicate the optimal mix of air and fuel for complete combustion, demonstrate that propane requires about 24 parts of air for every part of propane, whereas natural gas requires approximately 10 parts of air for every part of natural gas.

When analyzing combustion efficiency, having the correct amount of air is crucial for proper flame characteristics, avoidance of soot formation, and optimal heat production. Therefore, ensuring that there is enough air supplied when using propane is essential to achieve efficient combustion and prevent any hazardous conditions that can arise from improper air-fuel mixtures.