🤓 Based on our data, we think this question is relevant for Professor Findlater's class at TTU.
We are asked to determine the pKa of bromcresol green given that its blue and yellow form exists at pH 4.68.
In this problem, we are given equal concentrations of the blue (acid) and yellow (base) forms of bromcresol green (i.e. the indicator is at its equivalence point).
Recall that at equivalence point:
The acid-base indicator bromcresol green is a weak acid. The yellow acid and blue base forms of the indicator are present in equal concentrations in a solution when the pH is 4.68.
What is the pKa for bromcresol green?