7. The Fe+ ion present in acid mine drainage is colorless and surrounded 2 points by water molecules. If phenanthroline (Phe) is added, the solution turns

orange as a colored complex is formed according to the equation

(Fe3+xH2O) + Phe <--> (Fe3+xPhe) + H20. The color is commonly used

as an indicator of the Fe+ ion concentration. What would an increase in

color from light to dark orange indicate in this system?

a. addition of water to the system

O

b. an increase in the rate of the reverse reaction

O

c. an applied stress that shifted the equilibrium to favor the forward reaction

d. an applied stress that shifted the equilibrium to favor the reverse reaction