37. Solving a chemistry problem

5. A mixture of hydrochloric and boric acids was titrated potentiometrically with 0.1000 M NaOH sequentially: first, HCl was titrated (having consumed the volume of titrant V1), then glycerol was added to the solution and H3BO3 was titrated in the first step (obtaining the total volume of titrant V2).
Construct potentiometric titration curves in the coordinates pH - V and ΔpH / ΔV - V, determine the volumes V1 and V2 and calculate the concentration (g / l) of HCl and H3BO3, if 20.00 ml of a mixture of acids was taken for analysis and the following data were obtained during titration:

V NaOH, ml 0.00 0.40 0.60 0.80 1.00 1.05 1.10 1.20
pH 2.45 2.61 2.72 2.85 3.42 5.82 6.98 7.32

added glycerin:

V NaOH, ml 1.40 1.60 1.80 2.00 2.10 2.15 2.20 2.25 2.40
pH 5.88 6.26 6.70 7.28 7.67 8.10 9.03 9.75 10.28