In this experiment, you will titrate the two solutions (buffered and unbuffered solution) of citric
acid with 0.10 M NaOH , monitoring pH using pH Sensor and plot titration curves as pH versus
volume of the titrant NaOH.
Processing the data
1. To calculate the number of moles of NaOH used in both titrations, you will need the
volume at the equivalence point and the molarity of NaOH solution.
Data and Results
Complete the data table below.
Include the raw LoggerPro data and the graph.
Data Lemonade Citric Acid
Concentration of NaOH (M) 0.10 0.10
Initial volume of NaOH, mL 100 100
Final volume of NaOH, mL 28.4 48.9
NaOH volume added before the largest pH increase (mL) 57 16
NaOH volume added after the largest pH increase (mL) 62 26
Results
Volume of NaOH added at the equivalence point (mL) 59.5 21
Moles NaOH (mol)
Discussion hints
1. Determine which solution, buffered or unbuffered reacted with more moles of NaOH when the
equivalence point was reached?
2. Observe the graph of each titration. How does the titration curve of the buffered lemonade
compare to the curve of the unbuffered citric acid solution?
3. What is the formula of citric acid and the sodium salt of citric acid?
