Environmental Protection Agency (EPA) MVAC Certification

Which of the following substances will not react with ozone gas?

1. Fluorine

2. Chlorine

3. Nitrogen dioxide

4. Sulfur dioxide

The correct answer is: Fluorine

Fluorine is the correct answer because it is highly reactive and can actually contribute to the depletion of ozone in the atmosphere when it participates in reactions. However, in the context of the gases listed, fluorine's specific behavior is such that it does not have a direct reaction with ozone gas in the typical atmospheric conditions compared to the other choices, which do react with ozone in various environmental processes. Chlorine, nitrogen dioxide, and sulfur dioxide all have known interactions with ozone. Chlorine, like fluorine, contributes to ozone depletion in the stratosphere through reactions that break down ozone molecules. Nitrogen dioxide can react with ozone as part of photochemical reactions in the atmosphere, particularly impacting air quality and smog formation. Sulfur dioxide can also react with ozone, particularly in the context of acid rain formation and atmospheric chemistry, affecting environmental conditions. Overall, while fluorine may not typically react directly with ozone under standard conditions, the other substances actively participate in reactions with ozone, demonstrating why fluorine stands out in this question.