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

question 28

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. An ammonium buffer would work well at this pH:

• A) 5.6
• B) 7.0
• C) 9.0
• D) 11.0
• E) None of these

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Definitions:

Thalamus

A large mass of gray matter deeply situated in the forebrain at the topmost portion of the brainstem, functioning primarily as a central relay station for sensory impulses and as a center for pain perception.

Brain Stem

The posterior part of the brain, adjoining and structurally continuous with the spinal cord, responsible for basic vital life functions such as breathing and heartbeat.

Midbrain

A central part of the brainstem that plays an important role in vision, hearing, motor control, sleep/wake, arousal, and temperature regulation.

Pons

A part of the brainstem that links the medulla oblongata and the thalamus, critical for regulating breathing and sleep cycles.