Which of the following is NOT a use of chlorine?

Chlorine is primarily known for its applications in various chemical processes, particularly in the manufacture of hydrochloric acid and bleach, as well as in the production of certain plastics. Chlorine is involved in the production of hydrochloric acid through the reaction with sodium chloride and sulfuric acid, and it is a key component in the production of sodium hypochlorite, which is used in bleach. Furthermore, chlorine is vital in the synthesis of many types of polyvinyl chloride (PVC) plastics.

In contrast, while fertilizers are essential in agriculture, the primary chemicals used in fertilizer production typically do not involve chlorine. Fertilizers such as ammonium nitrate, urea, and phosphates are often produced from nitrogen and phosphorus compounds rather than chlorine. This differentiates the role of chlorine from that of the primary materials used in fertilizer production, highlighting its limited direct involvement in this specific application. Thus, among the provided options, the incorrect choice concerning chlorine's uses is its application in manufacturing fertilizers.