Which of the following best describes the characteristics of chlorine when used for disinfection in drinking water?

Chlorine is commonly used in drinking water treatment as a disinfectant due to its effectiveness at eliminating harmful pathogens. When discussing its physical characteristics, chlorine is recognized as a greenish-yellow gas. This distinctive coloration is one of the key identifiers of chlorine, which can also be noticeable by its strong, pungent smell.

Chlorine is nonflammable, which is critical for safety in water treatment facilities and during transportation. This property ensures that chlorine can be used safely without the risk of ignition, making it suitable for large-scale disinfection processes.

In terms of density, chlorine is heavier than air. This characteristic means that in the case of a leak, chlorine gas would tend to settle in low-lying areas rather than quickly dispersing into the atmosphere. Understanding these properties is crucial for safely handling and applying chlorine in water treatment processes.

While the other options present variations in properties such as flammability and density, the correct choice accurately captures the essential characteristics of chlorine, making it important for professionals in the field to recall these details for effective and safe water disinfection practices.