Use the following experimental titration data to calculate the unknown concentration and pH of the acid.
Observation:
The initial solution of acetic acid is clear and colourless. A few drops of phenolphthalein indicator are added to each sample. A dilute solution of potassium hydroxide is used as the titrant. As the mixture reaches the endpoint, flashed of pink colour are seen and the titrant is added drop by drop. The endpoint is reached when one drop of titrant turns the mixture a pale pink colour that does not fade.
Trial 1 Trial 2 Trial 3
Volume of HC2H5O2 (aq) used (mL) 10.00 10.00 10.00
3.00 x 10-4mol /L KOH in burette
Initial burette reading (mL) 0.00 25.30 50.51
Final burette reading (mL) 25.3 50.51 75.89