One beaker contains 10.0mL of acetic acid/sodium acetate buffer at maximum buffer capacity and another contains 10.0mL of pure water. Calculate the hydronium ion concentration and the pH after the addition of 0.25mL of 0.10M HCL to each one. What accounts for the difference in the hydronium ion concentrations? Explain this based on equilibrium concepts; in other words, saying that “one solution is a buffer” is not sufficient.

Ka of acetic acid = 1.8*10-5 Acetic acid/sodium acetate buffer Acetic acid 0.1M Sodium acetate 0.1M