Strong Iodine Solution
» Strong Iodine Solution contains, in each 100 mL, not less than 4.5 g and not more than 5.5 g of iodine (I), and not less than 9.5 g and not more than 10.5 g of potassium iodide (KI).
Strong Iodine Solution may be prepared by dissolving 50 g of Iodine and 100 g of Potassium Iodide in 100 mL of Purified Water, then adding Purified Water to make the product measure 1000 mL.
Packaging and storage Preserve in tight containers, preferably at a temperature not exceeding 35.
A: Dilute 1 drop with 10 mL of water, and add 1 mL of starch TS: a deep blue color is produced.
Assay for iodine Transfer 10.0 mL of Solution into a glass-stoppered, 500-mL flask, add 10 mL of water, and titrate with 0.1 N sodium thiosulfate VS, adding 3 mL of starch TS as the endpoint is approached. Each mL of 0.1 N sodium thiosulfate is equivalent to 12.69 mg of I.
Assay for potassium iodide Transfer 10.0 mL of Solution to a glass-stoppered, 500-mL flask, add 30 mL of water and 50 mL of hydrochloric acid, cool to room temperature, and titrate with 0.05 M potassium iodate VS until the dark brown solution that is produced becomes pale brown. Add 1 mL of amaranth TS, and continue the titration slowly until the red color just changes to yellow. The difference between the number of mL of 0.05 M potassium iodate used and half the number of mL of 0.1 N sodium thiosulfate used in the Assay for iodine, multiplied by 16.60, represents the number of mg of KI in the volume of the Solution taken.