Manganese (Mn) in steel may be determined upon dissolution as manganese (VII) after oxidation from the manganese oxidation state (II). This procedure calls for three oxidizing agents. The goal of this experiment was to determine the mass percent of manganese in an unknown steel sample using methods of visible spectroscopy and volumetric analysis. The process involves standardizing potassium permanganate with sodium oxalate and measuring absorbance to create a calibration curve, ultimately quantifying manganese concentration in. This document specifies a spectrophotometric method for the determination of manganese in steel and cast iron. Covers principles, reactions, cuvettes, and calibration curves.