In a laboratory experiment involving the neutralization of vinegar using 0.400 N NaOH, the following data was collected (trial #, volume of vinegar, volume of base):
Trial 1: 10.00 mL, 17.99 mL
Trial 2: 15.27 mL, 28.39 mL
Trial 3: 20.14 mL, 36.58 mL
If the correct mass percentage of HC2H3O2 in the vinegar is 5.40%, why does trial 2 give the best results. What is the percent error of this trial?