If the initial pH of a buffer solution that contains 0.150 mol of propanoic acid (C2H5OOH, Ka = 1.35 × 10-5) and 0.100 mol of potassium propionate (C2H5COOK) is 4.71, determine the final pH of 1.20 L of the buffer solution after 7.00 mL of 1.5 M HBr is added.
a 3.88
b 3.28
c 4.62
d 4.03
e 5.11
