Determination of Iodide

Procedure

Pipette 25.00mL of iodide solution into stoppered bottle. Add 25 mL of water, 60 mL of conc. HCl and 5mL of methelene chloride into it. Allow the solution to aquire room temperature. Add a portion of 0.025M potassium iodate with a burette and shake well (organic layer becomes purple due to iodine). Add small portions of potassium iodate occasionally, after each addition shake well. When organic layer changes purple to light color, add potassium iodate drop by drop and shake well. At the end point purple color disappears completely.