When Dr. Farrell was a graduate student, he once made up a pH 8.0 sodium acetate buffer. Why would the casual observer to this buffering faux pas come to the conclusion that he had the intellectual agility of a small soap dish?
Try this for size. There may be other reasons why this is not such a good buffer for pH = 8.0
pH = pKa + log (base/acid)
8.0 = 4.76 + log (base/acid)
8-4.76 = 3.24 = log (base/acid)
B/A = 1,738; therefore,
base (acetate in this case) = 1,738(A). Thus suppose we start with 1 mol acetic acid (A), then acetate mut be 1,738 mols. Could you dissolve almost 2 kmol sodium acetate (is that about 142 kg?) in 60 g acetic acid.
no
To understand why a casual observer might make such a conclusion, let's analyze the situation. The key mistake here is that Dr. Farrell made a pH 8.0 sodium acetate buffer. The pH of a buffer solution is determined by the pKa of the conjugate acid-base pair, where the most effective buffering occurs when the pH is close to the pKa value.
In the case of sodium acetate, its pKa value is around 4.76. This means that the sodium acetate buffer is most effective in the pH range around 4.76, as it can resist changes in pH by accepting or donating protons. However, Dr. Farrell mistakenly made a buffer with a pH of 8.0, which is significantly higher than the pKa.
A casual observer, who is not aware of the specific chemistry and principles behind buffer solutions, might see this error and assume that Dr. Farrell lacks intellectual agility. This conclusion is based on the assumption that someone with sufficient knowledge in chemistry, specifically buffers, would know that a pH 8.0 sodium acetate buffer is not effective. Hence, the observer may perceive this error as a sign of a lack of understanding or attention to detail.
However, it's important to note that everyone makes mistakes, even in areas where they have expertise. So, it's important not to jump to conclusions or make judgments solely based on one incident.