Determination of Hydrogen Peroxide by Iodometric Titration

Determination of Hydrogen Peroxide by Iodometric Titration

Question 1

H2O2 oxidizes iodide to iodine in the presence of acid and starch solution. The iodine formed is titrated with thiosulfate solution, incorporating a starch indicator.

H2O2 + 2 KI + H2SO4 ----> I2 + K2SO4 + 2 H2O I2 + 2 Na2S2O3 ----> Na2S4O6 + 2 NaI

Reagents

Potassium iodide solution (1% w/v). Dissolve 1.0 grams KI into 100 mLs demineralized water. Store capped in cool place away from light. Yellow-orange tinted KI solution indicates some air oxidation to iodine, which can be removed by adding a 1-2 ...