Question

A beaker with 1.30×10^2 mL of an acetic acid buffer with a pH of 5.000 is sitting on a benchtop. The total molarity of acid and conjugate base in this buffer is 0.100 M. A student adds 7.40 mL of a 0.400 M HCl solution to the beaker. How much will the pH change? The pKa of acetic acid is 4.740.

Answer 1

So the pH of the Acetic Acid buffer solution was 5.000 before the addition of HCl solution. By these calculations, the pH of the buffer solution after the addition of HCl is 4.600. So the change in pH of the buffer solution is 0.400