106. Solving a chemistry problem

6. The analyzed solution contains nitrate ions. To determine them, a galvanic circuit was made up of an indicator nitrate-selective electrode and a silver chloride reference electrode, the EMF of five reference solutions with a known concentration of nitrate ions was measured, and the following results were obtained:
С(NO3-), mol/l 0.00001 0.0001 0.001 0.01 0.1
E, mV 330 275 225 170 120
Under the same conditions, the EMF of the circuit with the analyzed solution was measured and found to be 250 mV. Determine the titer of nitrate ions in the analyzed solution using the calibration curve method.