Question

In the study of biochemical processes, a common buffering agent is the weak base trishydroxymethylaminomethane, (HOCH2)3CNH2, often abbreviated as Tris. At 25 ∘C, Tris has a pKb of 5.91.

The hydrochloride of Tris is (HOCH2)3CNH3Cl, which can be abbreviated as TrisHCl.

PART A

What volume of 10.0 M NaOH is needed to prepare a buffer with a pH of 7.79 using 31.52 g of TrisHCl?

Ans - 6.7mL.

PART B

The buffer from Part A is diluted to 1.00 L. To half of it (500. mL), you add 0.0100 mol of hydrogen ions without changing the volume. What is the pH of the final solution?

Ans - 7.58

PART C

What additional volume of 10.0 M HCl would be needed to exhaust the remaining capacity of the buffer after the reaction described in Part B? In other words, how much more of this HCl solution is required to consume the remaining Tris in the buffer?

Express your answer in milliliters using two significant figures.

NOTE: I NEED HELP WITH PART C. THE ANSWERS TO THE PRIOR PARTS WHERE PROVIDED BECAUSE THEY WOULD BE NEEDED IN SOLVING FOR PART C.