A beaker with 120 ml of an acetic acid buffer with a pH of 5.00 is sitting on a benchtop. The total molarity of acid and conjugate base in this buffer is 0.100 M. A student adds 8.40 ml of a 0.250 M HCl solution to the beaker. How much will the pH change? The pKa of acetic acid is 4.760.