General Information:
One liter of this solution contains 12.690 g of iodine (I, atomic weight: 126.90).
Procedure:
Weigh about 14 g iodine, dissolve in 100 ml of potassium iodide solution and add 3 drops of hydrochloric acid and water to make 1,000 ml. Store in a bottle with a ground-glass stopper, and restandardize frequently.
Weigh about 14 g iodine, dissolve in 100 ml of potassium iodide solution and add 3 drops of hydrochloric acid and water to make 1,000 ml. Store in a bottle with a ground-glass stopper, and restandardize frequently.
Standardization:
Weigh accurately about 0.15 g of arsenic trioxide (standard reagent), previously powdered and dried at 100ˆ to constant weight, and dissolve it in 20 ml of 1 mol/l sodium hydroxide by heating if necessary. Add about 40 ml of water and 2 drops of methyl orange TS, and add diluted hydrochloric acid (1 ˠ 4) until the yellow color of the solution changes to light pink. Add 2 g of sodium hydrogen carbonate, about 50 ml of water, and 3 ml of
starch TS, and titrate with 0.05 mol/l iodine until a blue color persists.
starch TS, and titrate with 0.05 mol/l iodine until a blue color persists.
1 ml of 0.05 mol/l Iodine = 4.946 mg As2O3
