20. Solving a chemistry problem

78. Change in the potential of a silver chloride electrode at a chloride concentration of 100.00; 150.00 and 200.00 µg/l was 3.0, respectively; 4.2 and 5.8 mV. Determine the concentration of chlorides (%) in a sample weighing 9.0000 g, if the sample was dissolved and transferred to a 250.00 cm3 volumetric flask, an aliquot of 10.00 cm3 was transferred to a 50.00 cm3 volumetric flask and the measured potential of the silver chloride electrode in the resulting solution turned out to be 4.9 mV.