Chemistry experiment 28 - Iodine clock reaction HD

Famous iodine clock reaction: oxidation of potassium iodide by hydrogen peroxide. Mixture A: - 10 mL 2.0 M sulphuric acid - 10 mL 3% hydrogen peroxide - 80 mL water Mixture B: - Solution of 0.04 g sodium thiosulfate pentahydrate in 20 mL water - Solution of 0.9 g potassium iodide in 5 mL water - 4 mL starch solution - 71 mL water