Exhibit 2B
Contains Information on the PK's of Some Common

Multiple Choice

Exhibit 2B
Contains information on the pK's of some common buffers.
$\begin{array}{llrc}\text { Buffer } & \mathbf{p K} 1 & \mathbf{p K 2} & \mathbf{p K} 3 \\\hline \text { Acetate } & 4.75 & & \\\text { Ammonia } & 9.25 & & \\\text { Carbonic acid } & 6.37 & 10.20 & \\\text { Citric acid } & 3.09 & 4.75 & 5.41 \\\text { Formic Acid } & 3.75 & & \\\text { Phosphoric acid } & 2.14 & 7.20 & 12.4 \\\text { Pyruvic acid } & 2.50 & & \\\text { Tris } & 8.3 & &\end{array}$

-Refer to Exhibit 2B. Which of the following would make the best buffer at pH =10.0?

A) Acetic acid and sodium acetate
B) Tris and its acid form
C) H₂CO₃ and NaHCO₃
D) Na₂HPO₄ and NaH₂PO₄
E) NaHCO₃ and Na₂CO₃