Calculate the molarity of a NaOH solution if 34.17 mL of the NaOH solution were required to titrate 0.6321 g of KHP. KHP (204.23 g/mole) is the shorthand (not the chemical formula) for the primary standard potassium hydrogen phthalate, a monoprotic weak acid. A primary standard is a compound that can be obtained in very pure form, is highly stable, can be dried to remove surface moisture, and has high molecular mass to minimize relative weighing errors. Therefore, titration of a sample of KHP is often used to find the molarity of a solution of base.