Determination of Concentration by Oxidation-Reduction Titration - Kevin Champagne Period 5 Determination of Concentration by Oxidation-Reduction

Determination of Concentration by Oxidation-Reduction Titration

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Kevin Champagne 10/5/201 8 Period 5 Determination of Concentration by Oxidation-Reduction Titration Purpose: This experiment is designed to determine the concentration of hydrogen peroxide in a drugstore bottle by titrating it with standardized KMnO 4 . Pre-Lab Questions: 1. In this experiment we are using a graduated cylinder and a buret to measure precise volumes. Additionally, a flask is also useful for measuring precise volume. 2. 8H + + MnO 4 - + 5e - → Mn 2+ + 4H 2 O (The Mn goes from a +7 charge to a +2 charge) 3. H 2 O 2 → O 2 + 2H + + 2e - (The oxygen goes from a -1 charge to a neutral charge) 4. The two half reactions have a common multiple of 10e - , meaning that 10 mol e - are transferred in the balanced redox reaction. 5. Fe +2 → Fe +3 + e - 6. 5e - + 8H + + MnO 4 - → Mn 2+ + 4H 2 O (5 mol e - are transferred in this reaction) 7. Perhaps copper could work, since it has both +2 and +3 oxidation states. 8. We know that there is one MnO 4 - ion in potassium permanganate, so the mol ratio is 1:1. Thus, a. x mol MnO 4 - / 0.0201 L = 0.020 M b. x = 0.0004 mol MnO 4 - 9.
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