Digital Experimental Study on Precipitation and Step-By-Step Precipitation of Halogen Ions by AgNO3 Solution
DU Qin-Zhi1**, TAO Jia2, FU Xiao-Jian1, CHEN Shi-Hong2**, ZHANG Ming-Xiao2
1. Chongqing No.8 Secondary School, Chongqing 400030, China;
2. School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China
Abstract The equilibrium of precipitation and dissolution of insoluble silver halide electrolyte is a key point in middle school chemistry teaching. The MXLab21 advanced digital experimental system developed by our project team cooperated with the silver-sulfur ion electrode to explore the precipitation curves of Cl-, Br-, I- and their mixed ions with AgNO3 solution as titrant. The precipitation curves presented the change of electromotive force (E) with AgNO3 solution volume (V). The precipitation curves of three kinds of single ions could directly reflect the relationship between titration E jump range and solubility product of the corresponding precipitation and the change rule of titration E jump range. Through the precipitation curves of mixed ions, the feasibility of step by step precipitation was explored in the case of the mixture of two or three ions. The establishment of dynamic E-V curves of the precipitation and step-by-step precipitation of Cl-, Br-, I- plays an important role in middle school chemistry teaching, and is of great value to the development and cultivation of the core quality of chemistry.
DU Qin-Zhi, TAO Jia, FU Xiao-Jian, CHEN Shi-Hong, ZHANG Ming-Xiao. Digital Experimental Study on Precipitation and Step-By-Step Precipitation of Halogen Ions by AgNO3 Solution[J]. Chinese Journal of Chemical Education, 2021, 42(15): 84-90.
