Free chlorine residual includes which of the following?

Free chlorine residual consists of the forms of chlorine that are effective as disinfectants in water treatment. Specifically, it includes hypochlorous acid (HOCl) and hypochlorite ion (OCl-).

Hypochlorous acid is the more effective form of chlorine for disinfection because of its ability to penetrate microbial cell walls and react with internal cellular processes. On the other hand, hypochlorite ion, while also a disinfectant, is less effective than HOCl but still contributes to the overall free chlorine residual.

The presence of these two species in the free chlorine residual is crucial because they act as the active chlorine species that sanitize and disinfect water. Monitoring and maintaining an appropriate level of free chlorine residual are essential for effective water treatment and ensuring safe drinking water.