Relevant errors primarily involves measurement of the pH values at each point in the titration curve, which may not have been perfectly accurate. The calibration of the pH detectors may have been off and the measurements as a result may have been slightly off. Therefore, the data and the results may have been inaccurate due to measurement error of the pH detector. In addition, the solution titrated may not have had a consistent and accurate concentration and may have been contaminated.
Discussion Questions Using graphical analysis to determine the K a for phosphoric acid can result in an accurate K a value. However, several errors must be accounted for, such as measurement error of the pH detector which may be off due to calibration. In addition, other relevant errors such as contamination and observation error for determining the equivalence point can significantly alter the K a value determined from graphical analysis. Although it may get an accurate result, there are many relevant errors in graphical analysis that may result in an inaccurate K a value. It is important to degas soda before performing titration on it because the carbonation interferes with measurement and the results obtained from titration. The carbonation in soda is caused by added carbonic acid during the production. By degassing the soda, the majority of the carbonic acid can be ignored when calculating pH and the phosphoric acid can be specifically examined. References Lab notebook tors
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- Fall '12
- Sodium hydroxide, Phosphoric acid