Question

What ratio of sodium acetate to acetic acid would be required to form a buffer with a pH of 4.25? (The Ka of acetic acid is 1.8 × 10^(-5)).

Answer 1

To form a buffer with a pH of 4.25, the ratio of sodium acetate to acetic acid should be 1.78:1.

Step-by-step explanation:

To form a buffer with a pH of 4.25, we need to use the Henderson-Hasselbalch equation and the pKa value of acetic acid. The Henderson-Hasselbalch equation is pH = pKa + log([conjugate base]/[weak acid]). In this case, acetic acid is the weak acid and sodium acetate is the conjugate base. Given that the pKa of acetic acid is 4.756, we can rearrange the equation to solve for the ratio of sodium acetate to acetic acid:

4.25 = 4.756 + log([sodium acetate]/[acetic acid])

0.25 = log([sodium acetate]/[acetic acid])

10^(0.25) = [sodium acetate]/[acetic acid]

1.78 = [sodium acetate]/[acetic acid]
Therefore, the ratio of sodium acetate to acetic acid in the buffer should be 1.78:1.