a. You have 50 mL of a buffer solution that is 0.15 M in HA and 0.25 M in A-. Calculate the pH of the solution after you add 100 mL of 0.01 M HCl to the solution. The pKa of HA is 4.75.

b. You wish to prepare 100 mL of a buffer solution that is 0.025 M in carbonic acid (H2CO3). The pKa of H2CO3 is 6.351. Calculate the amount of H2CO3, in grams, that you will need to weigh out.

c. You wish to prepare 100 mL (total volume) of a buffer solution that is 0.025 M in carbonic acid, pH 7.25. You have solid H2CO3 and solid NaHCO3. Calculate how many grams of H2CO3 and HCO3- you need to weigh out to prepare this solution.
pKa=6.351