At a pH of 7.2, what is the molecular state of hypochlorous acid after chlorination of pool waters?

At a pH of 7.2, hypochlorous acid (HOCl) exists in a specific balance between its molecular form and its ionized form, which is the hypochlorite ion (OCl⁻). The given answer highlights that at this pH, about 62 percent of hypochlorous acid is in the molecular form. This is an important aspect of water chemistry, particularly for disinfection in pool waters.

The equilibrium between hypochlorous acid and hypochlorite ion is influenced by pH levels. Hypochlorous acid is more effective as a disinfectant when it is in its molecular form (HOCl). The percentage of the molecular form versus the ionized form shifts with changes in pH. At neutral pH levels around 7.2, the balance favors hypochlorous acid significantly, making it almost two-thirds of the total available chlorine in this state.

Understanding this balance is crucial for effective chlorine management in pool sanitation. If the pH were to move significantly higher or lower, the percentage of molecular hypochlorous acid would change, affecting its efficiency as a disinfectant. Therefore, recognizing that the molecular state of hypochlorous acid is approximately 62