56. Solving a chemistry problem

9. Construct curves of potentiometric titration in the coordinates E – V and E∆/∆V – V and determine the concentration of CaCl2 in the solution (g/l), if during titration of 20.0 ml of the analyzed solution 0.0500 N Hg2(NO3)2 ( fequiv = 1/2) received:
V(Hg2(NO3)2), ml 10.00 15.00 17.00 17.50 17.90 18.00 18.10 18.50 19.00
E, mV 382 411 442 457 498 613 679 700 709