What is produced when chlorine is added to water?

When chlorine is added to water, hypochlorous acid (HOCl) is primarily produced. This occurs through a chemical reaction where chlorine (Cl2) reacts with water (H2O), resulting in the formation of hypochlorous acid and hydrochloric acid (HCl) as a secondary product. The reaction can be described by the equation:

Cl2 + H2O → HOCl + HCl

Hypochlorous acid is significant because it is a strong oxidizer and has effective disinfection properties, making it widely used in water treatment processes to kill bacteria and other pathogens. The presence of HOCl makes it an effective agent for maintaining water quality.

Other options, such as chlorine gas, would not be produced as a primary product since it is the chlorine that is being added to the water, rather than being generated. Hydrochloric acid, while produced, is secondary and does not serve the primary purpose of disinfection. Ozone is not produced in significant quantities from the addition of chlorine to water; it is a different disinfectant that requires specific conditions to form. Thus, the focus on hypochlorous acid as the primary product highlights its vital role in water sanitation.