A21. Solution to Chemistry Problem #11046

21. From a 0.2000 g sample of steel, after appropriate processing, 100.0 ml of a solution containing MnO4- and Cr2O72- were prepared, its optical density was measured using light filters with aeff=533 nm and aeff=432 nm (A533, A432). 5.00 8.00 10.00 ml of a standard solution of permanganate (T(Mn)=0.0001090) or dichromate (T(Cr)=0.001210) were placed in six 100.0 ml measuring flasks, diluted with water to the mark, and photometric measurements were taken under the same conditions. Determine the mass fraction (%) of Mn and Cr in steel for:
Option 1
KMnO4 K2Cr2O7
V, ml 5.00 8.00 10.0 5.0 8.00 10.0 - - -
A533 0.230 0.365 0.460 - - - 0.280 0.330 0.370
A432 0.095 0.150 0.190 0.430 0.640 0.780 0.82 0.760 0.720