Final answer:
The pH of a weak acid solution with a 100-fold excess of the conjugate base can be calculated using the Henderson-Hasselbalch equation.
Step-by-step explanation:
The pH of a weak acid solution in which there is a 100-fold excess of the conjugate base (A-) versus the acid form (HA) can be determined using the Henderson-Hasselbalch approximation. The Henderson-Hasselbalch equation is given by:
pH = pKa + log([A-]/[HA])
In this case, since there is a 100-fold excess of A- compared to HA, the concentration of A- is 100 times greater than HA. Therefore, the log term in the Henderson-Hasselbalch equation becomes log(100) = 2.