Spectrophotometric Determination of Equilibrium Constant

Abstract

The main purpose of the experiment is to obtain Keq's value of an unknown solution. It was obtained by means of a calibration graph by plotting the concentration of FeSCN2+ ions vs. its absorbance. Formed the best fit line acted as the graph of calibration. The unknown solution's measured absorbance was then plugged into the y variable in the best fit line equation in order to get the concentration of FeSCN2+ at equilibrium. The concentration of FeSCN2+ at equilibrium was subtracted to the initial concentrations of Fe3+ and SCN- for finding equilibrium in their respective concentrations. Keq was calculated by the ratio of the product concentration and the reactant concentration of the reaction to their stoichiometric coefficients.