1. The problem statement, all variables and given/known data Calculate the theoretical volumes of 1.0 M Tris base, 1.0 N HCL or 0.2 NaOH, and water needed to prepare 50 ml of a 0.1 M Tris buffer pH 9.0. pKa of Tris: 8.21 2. Relevant equations Henderson-Hasselbalch: pH=pKa + log[A-]/[HA] 3. The attempt at a solution Honestly, I don't even know how to start. I know how to calculate moles of each, ratio of [Tris]/[Tris+] (I got 6.16 by 10^(9-8.21)), etc, but I don't what I actually need to use for the calculation... Help?