97. Solving a chemistry problem

2. Determination of iron content in ore using permanganatometry and spectrophotometry methods
Problem 3
To determine the iron content in ore using the redox titration method, a working solution of potassium permanganate titrant with an approximate concentration of 0.10 mol/l was prepared. To do this, 30 ml of potassium permanganate was diluted in 300 ml of distilled water. Standardization of the working solution was carried out according to the standard method by pipetting. Mohr´s salt solution (C = 0.2027 N) was used as the primary standard. The titration results are shown in the table.
Experiment number Volume of Mohr´s salt solution, ml Volume of KMnO4, ml
1 15.0 30.0
2 15.0 30.2
3 15.0 30.1

The volume of the problem solution is 200.0 ml. The titration results are shown in the table.
Experiment number Volume of problem solution Fe2, ml Volume of KMnO4, ml
1 25.0 19.5
2 25.0 19.3
3 25.0 19.5