User:Douglas M. Fox/Notebook/AU CHEM-571 F2011 Lab Support/2012/01/25

Project 3: Solution Preparations

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Project Objectives Standardization of NaOH (titrant) & HCl stock solutions Preparation of 2.7 mM chlorauric acid solution Preparation of buffer solutions Today's Tasks Standardization of NaOH titrant solution (trial 1) Using "0.2 M NaOH" stock solution as a titrant Using Orion 5-Star meter with pH electrode Meter calibrated with homemade 1:1 HAc/NaAc and 1:1 Borate buffers Potassium Hydrogen Phthalate (KHPth) is a primary standard for acid/base solutions Analyzed Data Dried 10 g KHPth overnight at 110 °C Placed 1.04 g KHPth in 250 mL Erlenmeyer flask & added 50 mL water (grad cyl) After dissolution, added 3 drops phenolphthalein Added base in 0.2 - 5 mL increments, measuring pH at each step Data file available in DropBox