Determination of iodate and iodide in a mixture

Procedure

(i) Pipette 10.00 mL of the solution into a 100mL titration flask which contains 50 mL of water and add 5mL of 2M sulfuric acid. Titrate liberated iodine with 0.1M sodium thiosulphate solution using starch the indicator.

(ii) Pipette 25.00mL of solution in to a separating funnel, add 15mL of methelene chloride and 5mL of 1M sulfuric acid into it. Shake well to dissolve liberated iodine in organic layer. When the two layers separate remove organic layer into the stoppered bottle which contains 50 mL of water. Reextract liberated iodine usind two portions of 15mL of methelene chloride and transfer both organic layers into same bottle. Titrate extracted iodine with 0.1M sodium thiosulphate. Divide the aqueous layer in to two portions. Add a little KI solution into one and a little potassium iodate solution into the other and record your observations. Explain the observations. Determine the concentration of potassium iodate and KI in the mixture.