In: Chemistry
If you add strong acid (such as HCl) to the Tris solution above(25mM solution in 200mL) you can lower the pH. Using the Henderson-Hasselbalch equation (H-H), calculate how much strong acid in mM is need to lower the pH from 10.4 to 8.0.
Remember pKa is 8.2.
You might start by determining the amount of acid and base you have at each pH using the H-H equation. Then compare the differences in this ratio between the two pH values.