One of the ferric thiocyanate solutions at a pH of 3.0 was placed into the Vernier Spectrophotometer and its absorbance at a wavelength at 446.8 nm was measured over time. The two reactions occurring over time are represented below. In this graph, the absorbance of FeSCN 2+ increases over time due to the progression of the Fenton reaction in solution. As the Fenton reaction proceeds, the Fe 3+ concentration increases and reacts with the excess SCN -that is present, thereby increasing the concentration and absorbance of ferric thiocyanate over time.