Which of the following acid-base pairs would work best for a laboratory experiment requiring a pH of 6.8? What molar ratios of the compounds would you use to prepare the solution?
a. 0.20 mol H2S / 0.13 mol HS-
b. 0.13 mol H2S / 0.20 mol HS-
c. 0.10 mol HCO3- / 0.26 mol CO32-
d. 0.26 mol HCO3- / 0.10 mol CO32-