24. Solution to Chemistry Problem

2. To determine the total alkalinity of biologically treated wastewater from a sulfate production facility, a 50 cm3 water sample was placed in a 100 cm3 measuring flask and diluted to the mark with distilled water. 25 cm3 of the analyzed solution and distilled water were added to the potentiometric titration cell, a combined glass electrode connected to a pH meter was immersed, and the sample was titrated with a 0.05 mol E/dm3 (k=0.9986) solution to a constant pH value of - 0.5. Calculate the alkalinity of the water (mol E/dm3) if one maximum (pH = 4.0) was observed on the differential curve of the potentiometric titration at a titrant volume of 1.20 cm3. The initial pH value for the analyzed sample is 7.8.