Which gas is heavier, chlorine or air?

Chlorine is indeed heavier than air. To understand why this is the correct answer, it’s important to look at the molecular weights of both gases. Air is primarily composed of nitrogen and oxygen, with an average molecular weight of roughly 29 g/mol. Chlorine (Cl2) has a molecular weight of about 70.9 g/mol. This significant difference in density means that chlorine gas is heavier than the average components of air and will settle lower in the atmosphere if released.

This concept is particularly relevant in wastewater treatment and environmental management because chlorine is commonly used for disinfection purposes. Its heavier-than-air property can pose safety risks in enclosed spaces, as it can accumulate and potentially lead to hazardous situations. Understanding the behavior of gases in relation to their weight can help in implementing safety measures when handling chlorine and other chemicals.