Chlorine is an oxidizing agent and is added to swimming pool water in order to disinfect it[1]. The problem is that there needs to be enough chlorine present to disinfect the water but not too much to cause problems to users. This means that the water needs regular testing. This can be achieved easily using a standard redox titration. Excess potassium iodide is added to a sample of the water. The free chlorine in the...