The molar ratio of HPO42- to H2PO4- in a solution is 1.4. What is the pH of the solution? Phosphoric acid (H3PO4) is a triprotic acid, with 3 pKa values: 2.14, 6.86, and 12.4.A. 2.3B. 12.5C. 7.0D. 6.2

In our discussion of the acid-base properties of individual amino acids, we indicated that most amino acids will be electrically neutral over a very broad range of pH values, so that the pI of an individual amino acid is a nearly meaningless quantity. By contrast, a full-length protein will be electrically neutral over a relatively narrow pH range — typically less than one pH unit. Thus the pI of a protein is a well-defined quantity. Why is this?

Formic acid has a pKa of 3.75; acetic acid has a pKa of 4.76. Which is the stronger acid? Does the stronger acid have a greater or lesser tendency to lose its proton than the weaker acid?

What is the pH of 40.0mL of a solution that is 0.13 M CN- and 0.21 M in HCN? For HCN, use Ka = 4.9 x 10-9.

What are the concentrations of acetic acid (pKa = 4.76) and acetate in a buffer solution of 0.20M at pH 4.5? Enter your answer to two significant figures.