Dissolve 3 g of potassium bromate and 15 g of potassium bromide in water to make 1000 mL, and standardize the solution as follows. Accurately measure about 25 mL of the solution into a 500-mL iodine flask, and dilute with 120 mL of water. Add 5 mL of hydrochloric acid, insert the stopper in the flask, and shake it gently. Then add 5 mL of potassium iodide TS, again insert the stopper, shake the mixture, allow it to stand for 5 minutes, and titrate the liberated iodine with 0.1 N sodium thiosulfate VS, adding 3 mL starch as the endpoint is approached.