To a 25.00 mL volumetric flask, a lab technician adds a 0.300 g sample of a weak monoprotic acid, HA, and dilutes to the mark with distilled water. The technician then titrates this weak acid solution with 0.0867 M KOH. She reaches the endpoint after adding 41.23 mL of the KOH solution. Determine the number of moles of the weak acid in the solution. moles of weak acid: mol Determine the molar mass of the weak acid. molar mass = g/mol After the technician adds 18.27 mL of the KOH solution, the pH of the mixture is 4.39. Determine the pKa of the weak acid. pKa =