Tayler Powell and Kayla Frye
March 20, 2009 Advanced Chemistry- 4th Block
Analysis of a Commercial Bleach
The objective of this experiment is finding the amount of hypochlorite ions present in a solution of bleach. It is determined by an oxidation-reduction titration, the iodine-thiosulfate titration procedure. In acid solution, hypochlorite ions oxidize iodide ions to form iodine, I2. The iodine that forms is then titrated, meaning the process of reacting a solution of unknown concentration with one of known concentration, with a standard solution of sodium thiosulfate. When the iodide is oxidized in an iodide ion, it dissolves very well with the aqueous solution, forming into a complex ion called triiodide ion. When concentrated, the color in the experiment will be a dark red/brown color. After diluting the solution the color will turn yellow, which will determine the end point. Next step would to be to add the starch to the solution which forms a blue complex.
The most common oxidizing agent in bleaches is sodium hypochlorite, also known as NaCLO. The bleach that we are using in our experiment contains oxidizing agents which is sodium hypochlorite. Titration is the process of reacting a solution of unknown concentration with one of known concentration. In this experiment we are finding the number of hypochlorite ions present in a solution of bleach. The method that we are using is the iodine-thiosulfate titration procedure. By using this procedure the iodide ion, I- is easily oxidized by the bleach hypochlorite, which forms iodine (I2).