Experiment 52 Potentiometric Titration of Phosphoric Acid in Soda Pop

Experiment 52 Potentiometric Titration of Phosphoric Acid in Soda Pop 

Prepare 500 mL of 0.10 N NaOH using freshly boiled water and standardize it with primary standard KHP, as done previously in Experiment 8 in Chapter 4. 

As long as the soda pop is carbonated, the carbonic acid is present along with the phosphoric acid, although at a much smaller concentration. Citric acid may also be present, but at a smaller concentration. The carbonic acid may be eliminated by degassing to remove the carbon dioxide. Your instructor may ask you to obtain titration curves (step 4 below) for both as received samples and 

The idea for this experiment came from Ildy Boer at the County College of Morris in Randolph, New Jersey. 

Pipet 25.00 mL of the degassed soda pop into a 250-mL Erlenmeyer flask Set up the titration experiment with pH probe and pH meter on an automatic stirrer. The standardized 0.10 N NaOH is the titrant. 

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