23. Solution to Chemistry Problem

2. To determine fluoride ions using the calibration graph method, a series of standard solutions were prepared and the potentials of the fluoride-selective electrode relative to the silver chloride reference electrode were measured. Using the data obtained, construct a calibration graph:
Cp, M 10-5 10-4 10-3 10-2 10-1
E, mV 330 275 225 170 120
Use the calibration graph to determine the concentration of fluoride ions (g/l) in the test sample if 15 ml of the test solution was placed in a 100 ml flask and the volume was brought up to the mark with the background solution. The potential of the fluoride-selective electrode in the resulting solution was 195 mV.