21. Solving a chemistry problem

2c. A sample of ore weighing m g was dissolved and, after appropriate treatment, Fe2+ ions were titrated with a solution of potassium permanganate using the photometric method. Construct a titration curve and calculate the mass fraction (%) of iron in the sample based on the following measurement results:

Option Weight of sample m, g Concentration of KMnO4 solution Optical density of solution after
addition, ml KMnO4
10.00
ml 12.00
ml 14.00
ml 15.00
ml 18.00
ml 20.00
ml
2 1.0200 T=0.003109 0.010 0.010 0.045 0.110 0.175 0.240