You are asked to make a buffer solution with a pH of 10 (ignore temperature effects), with a final concentration of 0.1 M in 1.0L total volume. You are asked to use carbonic acid (H2CO3; MW = 62 g/mole) to make this buffer solution. The reported values for carbonic acid are pKa1 = 6.4 and pKa2 = 10.3. To make this solution you will first dissolve the acid in 800 mL of distilled water, then add a volume of 10 M NaOH, followed by additional distilled water to bring the volume up to 1.0L. Address the following:

A) How much carbonic acid do you add to make your desired solution (in grams)?

B) How much 10M NaOH do you add to obtain the desired pH?

C) Wait a minute, what if instead you are provided with a 0.2 M solution of NaHCO3 and 0.4 M solution of Na2CO3…then how would you make the solution? It should be the same pka values as carbonic acid.

D) Turns out you can only get the amino acid lysine (in acid form, fully protonated). Perform the same calculations for (A) and (B) using this molecule (how much to add, how much 10 M NaOH to add). I believe you can use any of the pka's that Lysine has, just use 2.

E) If you overshoot regarding the pH, that is say it’s at pH 11 vs. 10, then can you just add some HCl to bring the pH down or should you start all over? Why?