Practical Techniques

Question 1

Devise a practical to determine the Ka of a weak acid.

Answer 1

1. Titrate the weak acid with the strong base
2. Measure the pH at regular intervals
3. Plot a graph of pH against the volume of strong base
4. Use the graph to find the pH at half equivalence point
5. A half neutralisation
   pH = pKa
   Therefore, Ka = 10^pKa