A 0.411-g sample of potassium hydrogen phthalate, KHC8H4O4 (molar mass=204.44 g/mol) is dissolved with 50 mL of deionized water in a 125 mL Erlenmeyer flask. The sample is titrated to the phenolphthalein endpoint with 15.17mL of a sodium hydroxide solution. What is the molar concentration of the NaOH solution? Express the molar concentration of NaOH to the correct number of significant figures?
A 25.00-mL aliquot of a nitric acid solution of unknown concentration is pipetted into a 125-mL Erlenmeyer flask and 2 drops of phenophthalein are added. The above sodium hydroxide solution (the titrant) is used to titrate the nitric acid solution (the analyte). If 16.77 mL of the titrant is dispensed from a buret in causing a color change of the phenolphthalein, what is the molar concentration of the nitric acid (a monoprotic acid) solution? Express the molar concentration of HNO3 to the correct number of significant figures.