A 22.6 mL sample of a weak monoprotic acid, HX, requires 50.0 mL of 0.050 M NaOH to reach the equivalence point. After the addition of 30.0 mL of NaOH, the pH is 4.90. What is the Ka of HX?
1 answer
Surely you have made a typo (or two). There is no way the pH can be 4.90. The equivalence point for the titration of a weak acid and strong base is approximately 8.3 or so. Adding BASE to that will make it higher, not lower.