Which of the following is a characteristic of chlorine gas?

Chlorine gas is well-known for its distinct characteristics, one of which is its pungent and irritating odor. It has a strong, bleach-like smell that can be quite overwhelming, even at low concentrations. This property makes it easily recognizable and alerts individuals to its presence, which is particularly important in scenarios where exposure to chlorine gas could be harmful. In addition to its strong odor, chlorine is also a respiratory irritant, which can cause discomfort in the throat and lungs, making it critical to handle with caution in any water treatment or industrial cleaning applications. The other options do not accurately reflect the nature of chlorine gas; it is not odorless, it is not considered highly flammable under normal conditions, and it can be toxic at high concentrations. Therefore, the identification of chlorine gas as pungent and irritating captures its most significant and dangerous characteristics.