87. Solving a chemistry problem

1. For the polarographic determination of the manganese content in steel by the method of additions, a weighed portion of a sample weighing 0.950 g was dissolved and, after appropriate treatment, the volume was brought to 150 ml. To take a polarogram, 15 ml were taken. this solution, brought the background solution to 50 ml; the measured height of the polarographic wave is 25mm. After adding 3 ml of a standard solution of manganese sulfate with a concentration c (1/2 MnSO4) = 0.04600 mol/l to the analyzed solution, the wave height increased to 38 mm. Determine the mass fraction of manganese in the analyzed steel sample.