What is the flammability range of propane?

The flammability range of a substance indicates the concentrations of that substance in the air that can ignite and sustain a combustion reaction. For propane, the flammability range is between 2.15% and 9.60% by volume in air. This means that if the concentration of propane is below 2.15%, it is too lean to ignite, and if it exceeds 9.60%, it is too rich to ignite. The correct choice reflects this specific range, making it essential for understanding safe handling and storage practices for propane in various industrial and residential environments.

The other options do not accurately represent the established flammability range of propane, which is why they are not suitable. Understanding the correct flammability range is crucial for preventing fire hazards associated with propane use.