6. Solving a chemistry problem

17. A weighing of technical salicylate sodium weighing 0.8606 g was dissolved in a volumetric flask with a capacity of 50.00 ml and the solution was brought to the mark with glacial acetic acid. Potentiometric "titration of 5.00 ml of the resulting solution of 0.1 M HCl4 in glacial acetic acid (K = 1.030) gave the following results:
K(HCl4), ml 4.00 4.20 4.40 4.60 4.80 5.00 5.20 5.40
E, mV 440 447 458 474 512 595 615 625
Build titration curves and calculate the mass fraction (%) of indifferent impurities in the preparation.