What is the specific gravity of chlorine gas?

The specific gravity of chlorine gas is approximately 2.5 when compared to air. Specific gravity is defined as the ratio of the density of a substance to the density of a reference substance, commonly air or water, depending on the context. For gases, air is the reference substance, and since chlorine is heavier than air, its specific gravity exceeds 1. This means that chlorine gas will tend to settle in low-lying areas when released into the atmosphere.

Understanding why the other specific gravities do not pertain to chlorine gas is important for grasping the characteristics of various substances. Values like 1.0 and 0.9 suggest substances that are similar to or lighter than air, which does not apply to chlorine gas. The values also indicate that chlorine gas behaves quite differently in terms of buoyancy in ambient conditions compared to lighter gases. The option of 3.0 is significantly high, suggesting a density much greater than that of most commonly encountered gases, which further confirms that chlorine, while heavy, is not as heavy as the materials that would result in such a high specific gravity.