Chlorine gas density relative to air is approximately how many times heavier?

Chlorine gas density relative to air is approximately how many times heavier?

• A. One and a half times heavier than air
• B. Three times heavier than air
• C. Less than air
• D. Two and a half times heavier than air

Answer: (D)

Chlorine gas is heavier than air because its molecular weight is much higher than that of air. Chlorine has a molecular weight of about 70.9 g/mol, while air averages around 29 g/mol. Since density at the same temperature and pressure is related to molecular weight, chlorine’s density is roughly 70.9/29 ≈ 2.4–2.5 times that of air. This means leaks tend to settle in low areas—basements, pits, drains, and along floors. In practice, this behavior calls for floor-level monitoring and good ventilation to prevent dangerous buildup. Therefore, the correct choice is that chlorine is about two and a half times heavier than air.

Chlorine gas is heavier than air because its molecular weight is much higher than that of air. Chlorine has a molecular weight of about 70.9 g/mol, while air averages around 29 g/mol. Since density at the same temperature and pressure is related to molecular weight, chlorine’s density is roughly 70.9/29 ≈ 2.4–2.5 times that of air. This means leaks tend to settle in low areas—basements, pits, drains, and along floors. In practice, this behavior calls for floor-level monitoring and good ventilation to prevent dangerous buildup. Therefore, the correct choice is that chlorine is about two and a half times heavier than air.