[2] L. L. Brunton, J. S Lazo and K. L. Parker, “Las Bases Farmacológicas de la Terapéutica,” McGraw Hill, Espa?a, 2006.

has been cited by the following article:

• TITLE: Determination of the pKa Value of Phenolphthalein by Means of Absorbance Measurements

  AUTHORS: Manuel Alonso, Sebastián P. Chapela, María L. Cristaldo, Inés Nievas, Hilda I. Burgos Oliver Gamondi, Carlos A. Stella

  KEYWORDS: Medical Science Teaching

  JOURNAL NAME: Creative Education, Vol.1 No.2, September 18, 2010

  ABSTRACT: We here report a laboratory protocol for the determination of the pKa value of an acid by means of determinations obtained with a spectrophotometer. Students determine the acidity constant (Ka) and the pKa associated with phenolphthalein from the absorbance values obtained from phenolphthalein solutions at different pHs. The present protocol for the determination of the pKa takes a very short time and is useful when teaching in conditions with limited equipment.