Question

A buffer is prepared by mixing 36.2 ml of 0.209 M NaOH with 138.1 ml of 0.231 M acetic acid. What is the pH of this buffer? (The pKa for acetic acid is 4.75.) Calculate the pH of this buffer after the addition of 0.179 g of solid NaOH.

Answer 1

To calculate the pH of the buffer, use the Henderson-Hasselbalch equation.

Step-by-step explanation:

To calculate the pH of the buffer, we need to use the Henderson-Hasselbalch equation:

pH = pKa + log(base/acid)

Given that the pKa for acetic acid is 4.75, the base is the concentration of NaOH, and the acid is the concentration of acetic acid. We can calculate the concentration of NaOH by using the formula:

NaOH (mol) = (mass of NaOH (g) / molar mass of NaOH (g/mol)) / volume of solution (L)

Substituting the values into the Henderson-Hasselbalch equation, we can calculate the pH of the buffer.