A solution of an unknown acid is prepared by dissolving 0.250 gof the unknown in water to produce a total volume of 100.0 mL. Halfof this solution is titrated to a phenolphthalein endpoint,requiring 12.2 mL of 0.0988 M KOH solution. The titrated solutionis re-combined with the other half of the un-titrated acid and thepH of the resulting solution is measured to be 4.02. What is arethe Ka value for the acid and the molar mass of the acid?
