Question

Match each weak acid with the pH value at which it would buffer. pH 3 pH 5 pH 9 Answer Bank hydrazoic acid (pK, of 4.6) acetic acid (pk, of 4 76 boric acid (pK, of 9.24) ammonium (pK, of 9.25) chloroacetic acid (pK, of 2.87) formic acid (pk, of 3.8)

Answer 1

The best buffer systems have weak acids and their conjugate bases or weak bases and their conjugate acids that have pKa values close to the desired pH range. The correct matches for the given weak acids and pH values are hydrazoic acid (pKa of 4.6) at pH 5, acetic acid (pKa of 4.76) at pH 5, and boric acid (pKa of 9.24) at pH 9.

Step-by-step explanation:

A buffer is a solution that resists changes in pH when small amounts of acid or base are added. The best buffer systems have weak acids and their conjugate bases or weak bases and their conjugate acids that have pKa values close to the desired pH range.

Based on the given information, the correct matches of weak acids with the pH values at which they would buffer are:

• Hydrazoic acid (pKa of 4.6) - pH 5
• Acetic acid (pKa of 4.76) - pH 5
• Boric acid (pKa of 9.24) - pH 9