Preparation and standardization of 0.05 M Potassium Iodate USP Volumetric Solution
Dissolve 10.700 g of Potassium Iodate, previously dried at 110°C to constant weight, in water to make 1000.0 mL.
Take 15.0 mL of 0.05 M Potassium Iodate solution in a 250 mL iodine flask, add 3 g of Potassium Iodide and 3 mL of Hydrochloric acid previously diluted with 10 mL of water. Stopper immediately, and allow to stand in the dark for 5 minutes. Then add 50 mL of cold water, and titrate the liberated Iodine with freshly standardized 0.1 N Sodium Thiosulfate volumetric solution. Add 3 mL starch indicator solution near the end of the titration, and continue to the absence of the blue starch-iodine complex.
Molarity (M) = [Titration reading (in ml) x Normality of 0.1 N Na2S2O3]/[Volume of KIO3 (in ml)x 6]
Limit: 0.05 M ± 5 % (0.0475 M – 0.0525 M)
3. PREPARATION OF INDICATORS / REAGENTS:
a. Starch indicator solution:
Mix 1 g of soluble starch with 10 mg of red mercuric iodide and sufficient cold water to make a thin paste. Add 200 mL of boiling water, and boil for 1 minute with continuous stirring. Cool, and use only the clear solution.
b. 0.1 N Sodium Thiosulphate VS:
Preparation and standardisation as per respective procedure.
4. STORAGE CONDITION:
Store in glass stoppered bottles.