What form does chlorine take after the breakpoint is reached?

When the breakpoint chlorination is achieved, chlorine is transformed into free chlorine. This process involves adding enough chlorine to oxidize all forms of combined chlorine, such as chloramines, and any other organic material in the water. Once this breakpoint is reached, the remaining chlorine that is present in the water is referred to as free chlorine.

Free chlorine is the active form of chlorine that is effective in disinfection, providing the necessary sanitation for swimming pools by eliminating pathogens and maintaining water clarity. This free chlorine is crucial for ensuring the safety of the pool water for swimmers, as it effectively kills bacteria and viruses.

Combined chlorine, which is formed when chlorine combines with ammonia or organic matter, becomes neutralized at the breakpoint, while chloramines, which can contribute to unpleasant odors and skin irritation, are also broken down. Inactive chlorine is not a commonly used term in water chemistry and does not represent the active form of chlorine needed for effective sanitation. Thus, free chlorine is the correct identification of chlorine after reaching the breakpoint.