An enzyme-catalyzed reaction was carried out in a 0.2M �Tris� buffer, pH 7.8. As a result of the reaction, 0.03 mole/liter of H+ was produced. (pKa of Tris =8.1) (a) What was the ratio of Tris+ (conjugate acid) / Triso (Conjugate base) at the start of the reaction? (b) What are the concentration of Tris+ and Triso at the start of the reaction? (c) Show the reaction by which the buffer maintained a near constant pH. (d) What were the concentration of Tris+ and Triso at the end of the reaction? (e) What was the pH at the end of the reaction? (f) What would the final pH be if no buffer were present?

To answer these questions, we need to understand the concept of a buffer solution and how it works. A buffer solution is a solution that resists changes in pH when small amounts of acid or base are added to it. It consists of a weak acid and its conjugate base, or a weak base and its conjugate acid.

(a) To determine the ratio of Tris+ (conjugate acid) to Triso (conjugate base) at the start of the reaction, we can make use of the Henderson-Hasselbalch equation:

pH = pKa + log([A-]/[HA])

In this case, Tris+ corresponds to the "A-" and Triso corresponds to the "HA". The given pH is 7.8, and the pKa of Tris is 8.1. By plugging these values into the equation, we can determine the ratio [A-]/[HA], which is the same as Triso/Tris+.

(b) To find the concentration of Tris+ and Triso at the start of the reaction, we'll need the total concentration of the buffer. This information is not given in the question, but let's assume it to be 0.2M, as mentioned that the buffer is 0.2M.

(c) To understand how the buffer maintains a near constant pH, we need to show the reaction by which it does so. In this case, the reaction involves the Tris buffer acting as a weak acid in response to the production of H+ ions:

Tris+ + H2O ⇌ Triso + H+

(d) To determine the concentration of Tris+ and Triso at the end of the reaction, we'll need more information regarding the final volume of the reaction mixture or the amount of enzyme present. Without this information, we can't provide an exact answer.

(e) To find the pH at the end of the reaction, you would need to know the concentration of Tris+ and Triso at the end of the reaction, as well as the total volume of the reaction mixture. Without these values, we can't calculate the pH.

(f) If no buffer were present, the pH would change significantly due to the production of H+ ions. The exact final pH would depend on the amount of H+ ions produced and the volume of the reaction mixture. Without this information, we can't give a specific value for the final pH.

In summary, to fully answer these questions, we would need additional information such as the total concentration of the buffer, the final volume of the reaction mixture, or the amount of enzyme present.