Worksheet 3.1. Preparation of an indicator solution for determination of residual chlorine
· make in two separate bottles, a KI and a starch solution of 3 g in 100 ml deionised water · heat the starch solution until it becomes clear · dissolve in the mean time the KI · stock the two labelled bottles in the refrigerator · to check the presence of chlorine, put a few drops of each solution in a small sample · if your sample turns blue,
chlorine is still present |