15. Solving a chemistry problem

271. To determine the electrolyte concentration, 10.0 ml of the solution was placed in a volumetric flask with a capacity of 100 ml, brought to the mark with water. Then 10 ml of the solution was passed through a column with a cation exchanger in H-form. The eluate and washings were collected in a beaker and titrated potentiometrically with 0.1 M NaOH solution, using V (ml) of the titrant solution. Calculate the electrolyte concentration (g/l) from the following data:
Electrolyte KNO3 NaNO3 CuSO4 NiSO4
V(NaOH), ml 1.98 2.15 1.67 0.89