We are preparing an acetate buffer at pH 4.5 with 0.01 M solutions of acetic acid (pKₐ = 4.8)and sodium acetate.Which of the following should the volume of acetic acid be compared to the volume of sodium acetate solution?
A)less than half
B)exactly half
C)equal to
D)about twice

Question

Quizplus · Accepted Answer

To prepare an acetate buffer, the ratio of the concentration of the acid and its conjugate base should be between 1:1 and 10:1. Since the pKa of acetic acid (4.8) is close to the desired pH of the buffer (4.5), the buffer will be most effective if the concentration of the acid and its conjugate base are approximately equal (i.e., in a 1:1 ratio). Therefore, the volume of acetic acid should be about twice the volume of the sodium acetate solution. Hence, the correct answer is D.

We Are Preparing an Acetate Buffer at PH 4