High School

A buffer is prepared by mixing 38.2 mL of 0.183 M NaOH with 125.7 mL of 0.231 M acetic acid. What is the pH of this buffer? (The pKa for acetic acid is 4.75.)

Answer :

Final answer:

The pH of a buffer can be calculated using the Henderson-Hasselbalch equation. First, we need to determine the moles of acid and base using their molarity and volume. The substance that is left after the acid-base reaction will determine the pH of the buffer solution.

Explanation:

The question is asking for the pH of a buffer solution prepared by mixing a known volume and molarity of NaOH (a strong base) with a known volume and molarity of acetic acid (a weak acid). We can use the Henderson-Hasselbalch equation, which is pH = pKa + log([A-]/[HA]), where [A-] is the molar concentration of the base (the acetate ion in this case), and [HA] is the molar concentration of the acid (acetic acid in this case).

To begin, we need to calculate the moles of NaOH and acetic acid from their volume and molarity. This gives us moles = volume (L) * molarity (M). Then we utilize the concept that in a buffer, the strong substance (NaOH in this case) reacts completely with the weak one (acetic acid in this case) until one of them is used up. The leftover substance determines the pH of the resulting buffer solution.

We then use the information of the leftover substance (either base or acid, whichever is in excess) to perform the Henderson-Hasselbalch equation and get the final pH of the solution.

Learn more about Buffer pH here:

https://brainly.com/question/32648797

#SPJ11

Other Questions