COMPARATIVE STUDY OF SODIUM HYPOCHLORITE CONCENTRATIONS IN SELECTED COMMERCIAL INDUSTRIAL BLEACHES

Comparative Study of Sodium Hypochlorite Concentrations in Selected Commercial Industrial Bleach was done. Samples of Industrial Bleach were bought from the market and the analysis for the concentration of sodium hypochlorite was carried out on them. The samples are Bleach produced in the chemistry laboratory by the students (Students Bleach), HYPO (Commercial), and JIK (Commercial). Triplicate titration was done on each of the samples and results gotten. Classical method of analysis was used. A multi-step method was used to titrate sodium hypochlorite. In the first step sodium hypochlorite, hydrochloric acid, iodide ion, and starch are combined to form a starch– triiodide complex. In this step there are three reactions that took place. The result of these three reactions is that when sodium hypochlorite is present, the starch-triiodide complex is produced. This is useful because the result of these three reactions is the formation of a dark blue complex that has a concentration that is proportional to the amount of sodium hypochlorite in the solution. In the next step, the starch-triiodide product was titrated by sodium thiosulfate to form a colourless solution of iodide, dithionate, and uncomplexed starch. The hypochlorite acts as a limiting reagent, determining how much triiodide is produced. The triiodide-starch complex was then titrated with the thiosulfate to determine the concentration of the complex formed. This was then used to calculate the initial concentration of the sodium hypochlorite. The concentration of the three brands of the Bleach analysed (Stds, HYPO, JIK) are respectively 2.76±0.01, 2.79±0.02, 2.48±0.01 and are within the range of accepted hypochlorite in Bleach.