Final answer:
The equilibrium expression for the bromophenol blue indicator is Keq = [(C19H8Br4O5S)2-H] / [(C19H8Br4O5S)-]
Step-by-step explanation:
The equilibrium expression for the reversible reaction of the pH indicator bromophenol blue, which can be represented as (C19H8Br4O5S)- ↔ (C19H8Br4O5S)2-H, is:
Keq = [(C19H8Br4O5S)2-H] / [(C19H8Br4O5S)-]
The concentrations (or partial pressures) of the species involved in the reaction are shown in brackets. The concentration (or partial pressure) of the products is represented by the numerator, and the concentration (or partial pressure) of the reactants is represented by the denominator.