Abstract Redox and electrolysis are the key contents of middle school chemistry. The MXLab21 advanced digital experimental system developed by our project team was used to electrolyze Fe2(SO4)3 to generate Fe2+, which was used to determine the concentration of KMnO4 through direct titration method, and the concentration of H2O2 in the disinfectant through the back titration method. The experimental conditions for constant current electrolysis including the concentration of Fe2(SO4)3 and the magnitude of electrolysis current had been optimized. Compared with the conventional digital instrument or handheld technology, the advantage of this digital experiment system was that it had its own electrolysis, stirring and control system. It could use substances produced by electrolysis to achieve accurate determination of the substance while electrolyzing, and the determination time was short (no more than 4 min). The end point of titration was estimated automatically by presetting the end point potential value, which was not only convenient and accurate, but also presented a real-time and intuitive dynamic curve of potential and electric quantity changes with time to facilitate students to understand the microscopic nature of electrolysis and redox titration reactions. It was of great value for middle school chemistry teaching and the cultivation of chemistry discipline core literacy.
DU Qin-Zhi, WEN Xia, XIONG Xiao-Qing, CHEN Shi-Hong, ZHANG Ming-Xiao. Digital Experiment on Determination of Hydrogen Peroxide Concentration in Disinfectant by Back Titration Using Ferrous Ion Produced by Electrolysis[J]. Chinese Journal of Chemical Education, 2022, 43(11): 111-117.
