Multiple Choice
A typical amino acid has a carboxylic acid and an amine with pKa values of 2.3 and 9.6, respectively. In a solution of pH 4.5, which of the following best describes the protonation and charge state of the amino acid?
A) carboxylic acid: protonated and neutral; amine: deprotonated and negative
B) carboxylic acid: protonated and neutral; amine: protonated and neutral
C) carboxylic acid: deprotonated and negative; amine: protonated and neutral
D) carboxylic acid: deprotonated and negative; amine: protonated and positive
E) carboxylic acid: deprotonated and negative; amine: deprotonated and neutral
Correct Answer:

Verified
Correct Answer:
Verified
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