Final answer:
A buffer, such as a mixture of acetic acid and sodium acetate, helps to maintain a consistent pH level within a solution, even with the addition of acids or bases. By adjusting the concentrations of the weak acid and its conjugate base, the pH of the buffer can be manipulated. Sodium acetate buffers are often used in biochemical studies to prevent pH changes that could affect the activity of enzymes and other cellular components.
Step-by-step explanation:
A buffer is a solution that can maintain a stable pH level, even when small amounts of acid or base are added. To create an effective buffer, a weak acid and its conjugate base are used in combination. The pH of the buffer can be altered depending on the ratio of these two components. For instance, a mixture of acetic acid and sodium acetate can create a buffer with a desired pH.
In the case of a sodium acetate buffer, the pH calculation involves acetic acid (CH₃COOH), a weak acid, and sodium acetate (CH₃COONa), its conjugate base. By using the Henderson-Hasselbalch equation, the pH of a buffer can be estimated when the concentrations of the weak acid and its conjugate base are known.
Take for example a solution with 0.10 M acetic acid and 0.10 M sodium acetate. This buffer solution would have a certain pH value that can be calculated. Additionally, after the addition of a small amount of 0.10 M NaOH to this buffer, the pH would change minimally compared to the same addition to an unbuffered solution. This highlights the buffer's capacity to withstand pH changes upon the addition of an acid or base.
Buffers are crucial in biochemical experiments where maintaining a constant pH is necessary for accurate results, such as in enzyme studies. The sodium acetate buffer, for instance, can be used at a pH of around 4.74 for biochemical assessments. However, by adjusting the concentrations or by selecting different weak acids and bases, buffers with different pH levels can be prepared, like a pH 8.0 buffer made from trisHCl and tris with respective concentrations.