A medicinal taste in water may develop when free chlorine reacts with what?

A medicinal taste in water is commonly associated with the reaction of free chlorine with phenols. When chlorinated water reacts with phenolic compounds, which can originate from decaying organic matter or certain industrial processes, it can lead to the formation of chlorinated phenols. These compounds may exhibit medicinal or chemical-like flavors and odors that can be quite noticeable when present even at low concentrations.

Phenols, along with their compounds, can cause various sensory issues in water, including undesirable tastes and odors. Thus, their reaction with free chlorine is significant in water treatment processes, where maintaining water quality and palatability is crucial. Other options like chlorides, aromatics, and sulfur do not typically lead to the formation of compounds that impart a medicinal taste as phenols do, emphasizing the unique behavior of phenols in this context.