List weak acid/conjugate base pairs that you could use to prepare buffers with the following pH values by mixing equal moles of the acid and base in...

List weak acid/conjugate base pairs that you could use to prepare buffers with the following pH values by mixing equal moles of the acid and base in 1 Liter of water. For each one, list the formulas for the acid and the base.

a. pH = 1.96

b. pH = 3.39

c. pH = 8.70

d. pH = 9.21