In this experiment, students will prepare a reaction mixture containing the solutions of iron (III) nitrate, potassium thiocyanate, & distilled water inside of a beaker. What indication of chemical change will be used to study the equilibrium constant of the reaction in this experiment?

You don't give enough information for me to know what you're doing. Of course the solution will turn a deep red color due to the presence of iron thioyanate but that's allI can tell from the information given.