Chemistry Experiment: The Consequences Of Dicture Benzoic Acid
Water at 25° Celsius always has an auto-ionization constant of 1.0 × 10-14 and HCl is a strong acid which means it has a high Ka of 1 or higher. When HCl is the primary source of H3O+ ions, the pH will always be below 7 because of its high dissociation constant creating an abundance of H3O+ ions. When the HCl solution becomes so diluted that water is the major source of H3O+ ions, the pH will still never go above 7 because the Kw of water will ensure that the H3O+ is 1.0 × 10-7 giving you a pH of 7 exactly, never higher. In order for the solution to have a pH of 8 some sort of base must be added to the solution.
You could determine Ka for benzoic acid by measuring the pH of a 0.010 M solution of benzoic acid. Why is the graphical method you used in this experiment a better way of determining