The purpose should include a majority of the topics and techniques covered in the experiment. The procedure section should cite the lab manual and include any changes made to the procedure during lab work.

The data section should include a balanced equation of each of the acid dissociations being studied; there should be three sets of equations. These will include, one equation with the reaction of NaOH and HCl, the three neutralization reactions for phosphoric acid by NaOH and the three neutralization reaction for citric acid by NaOH. The concentration of NaOH for each of the two trials with standard HCl should be reported and averaged. The concentration and K_a values of phosphoric acid and citric acid should be reported. More than one K_a may be determinable for a given acid, depending on the number of equivalence points. Lastly include the number of moles of citric acid found in a can of 7-UP©.

The calculation section should include the following: Four titration graphs. Two HCl graphs, one phosphoric acid graph and one citric acid graph. Each graph should be pH vs the total volume of titrant added. All graphing guidelines apply. DO NOT add a trend line to these graph, if you would like to add a line, a moving average would be acceptable. Sample calculations for determining the molarity of NaOH, phosphoric acid, and citric acid should be included. The concentration of NaOH can be determined in the following way:

The concentration of phosphoric acid and citric acid can be found in the following way:

Sample calculations for K_a values: Recall that pH=pK_a at ½ equivalence point and that pK_a= - log (K_a). Theoretically there should be one equivalence point for the HCl titrations and more than one for the titration of phosphoric acid and citric acid. Using the K_a values you calculate for each acid calculate a percent error using the literature K_a values.

Finally show a sample calculation of the number of moles of citric acid in a can of 7-UP©. NOTE: There are 240 mL of 7-UP© in a can.

The conclusion should include several paragraphs with the following: the concentrations of HCl, NaOH, phosphoric acid and citric acid.  A discussion of the K_a values and the errors associated with them. A discussion of the differences in the titration curves for a weak acid and a strong acid. Finally discuss all possible errors.

Answer the following questions: