preview

Oxidation Titration

Decent Essays

Introduction/Theoretical Background: A common task in chemistry is the determination of a substance present in a product. If the product contains a substance that can be oxidized, then it is possible to determine the number of moles of that substance by titrating the sample with a solution of a strong oxidizing agent. In this lab, a solution of KMnO4, an oxidizing agent, will be standardized by titration with a solution containing a known concentration of iron (II) ions, (Fe+). The concentration of oxalic acid solution will be determined by titration with the MnO4- solution that had been standardized first. The purpose of this lab is to standardize a solution of potassium permanganate by redox titration with a standard solution of …show more content…

Add 20 mL of distilled water to each flask and swirl.
5. Warm the first flask to about 85°C on the hot plate.
6. Immediately titrate this solution with the standardized MnO4 solution from Part 1. Record both the initial and final buret readings in the Part 2 Data Table.
7. Repeat steps 5 and 6 with the second flask.

Data Table:

| Trial 1 | Trial 2 | Trial 3 | Volume of Fe2+ solution titrated | 10 mL | 10 mL | 10 mL | Initial volume of MnO4- solution | 3.5 mL | 14.5 mL | 24.8 mL | Final volume of MnO4- solution | 14.5 mL | 24.8 mL | 35.32 mL | Volume of MnO4- added | 11 mL | 10.3 mL | 10.52 mL |

| Trial 1 | Trial 2 | Volume of H2C2O4 solution titrated | 25 mL | 25 mL | Initial volume of MnO4- solution | 2 mL | 15 mL | Final volume of MnO4- solution | 15 mL | 28 mL | Volume of MnO4- added | 13 mL | 13 mL |

Calculations:

Balancing:
Reduction: 8H+ + MnO4- + 5e- -> Mn2+ + 4H2O
Oxidation : Fe2+ -> Fe3+ + e-
8H+ + MnO4- + 5e- -> Mn2+ + 4H2O
5Fe2+ -> 5Fe3+ + 5e-
Balanced overall: 8H+(aq) +MnO4-(aq) + 5Fe2+(aq) -> 5Fe3+(aq) + Mn2+(aq) + 4H2O(l)

Normality:
Number of electrons transferred = number of equivalents = 5
Equivalent weight: (39.10g/mol + 54.94g/mol + 4*16.00g/mol)/5 = 31.61g/mol Normality = 5M = 5 * .020M = .100N

Volumes: Trial 1:
FeSO4: 24.60mL - 14.76mL = 9.84mL
KMnO4: 26.20mL - 9.18mL = 17.02mL

Trial 2:
FeSO4: 34.59mL -

Get Access