Calculate the pH of the resultant solution when solutions of acids and/or bases are diluted or mixed

Acid/Base Reactions > Using Brønsted–Lowry Theory >

Problem Statement:

6mL 0.15M NaOH solution is added to 15mL 0.15M CH₃COOH solution. Calculate pH of the resulting solution [pKa = 4.74]

Solution:

The reaction between CH₃COOH and NaOH is as follows

From the above reaction, we can see that 1 mole of NaOH can neutralize the same amount of CH₃COOH to produce 1 mole of CH₃COONa.
Therefore, 6mL 0.15M NaOH can neutralize 6mL 0.15M CH₃COOH to produce 6mL 0.15M CH₃COONa

Now, remaining acid = (15 – 6)mL = 9mL
Produced salt = 6mL
Total volume of solution = (15 + 6)mL = 21mL