141. Solving a chemistry problem

In standard solutions of CdS04 with different activities of Cd2, the electrode potentials of the cadmium-selective electrode were measured relative to the silver chloride electrode:
aCd, mol/L.1,0*10^-11,0*10^-21,0*10^-3 1,0*10^-41,0*10^-5
—Е, mV 75,0 100 122 146 170
Based on these data, a calibration graph was constructed in the coordinates E - paCd.
The investigated solution of cadmium salt with a volume of 10.00 ml was diluted with water to 50.00 ml in a volumetric flask and the electrode potential of the cadmium-selective electrode was measured in the resulting solution (Ex):
Option 1
—Ex, mV. 94.0
Determine the activity of the test solution of cadmium salt (mol / l).