Repeat Experiment #2 using acetic acid unknown #2. Begin by measuring 5.00 mL of the unknown acetic acid solution using a 10 mL graduated cylinder. Add this to a 150 mL Erlenmeyer flask, along with 75.0 mL of water and 2 drops of phenolpthalein. Titrate the unknown using the 0.100 M NaOH solution. Perform this titration in triplicate, and report the average concentration of acetic acid determined from the three titrations. average concentration: