Question

Buffers and pH

1.(12 pts) A stock solution of Tris -HCl buffer sits on the shelf (0.6 M, pH 8.35). You remove 80 mL of the stock solution, add 12 mL of 0.75M HCl and dilute to 1 L. The pKa of Tris-HCl is 8.20.

(a) How many millimoles of both forms of Tris -HCl are present after you added the acid?

(b) What is the final buffer concentration in mM?

(c)What is the final pH of your buffer?

Can you show all work to confirm the answers below:

(a)U = 19.1 mmoles, P = 28.9

(b)48mM

(c)pH = 8.02