碘量法中一些基本的动力学问题的探讨

利用紫外-可见分光光度仪测量了I2挥发I、-在酸性介质中被溶解氧氧化的动力学过程,着重研究了容器形状、溶液体积、KI浓度、温度等因素对I2挥发速率的影响以及溶液酸度与I-氧化反应速率的关系。研究表明I2挥发符合一级动力学模型,而I-的氧化为表观零级反应。通过大量数据和图形,形象直观地从定量的角度阐述了碘量法中控制实验条件的重要性。

Discussion on the Basic Kinetic Points in Iodometry

Using Agilent 8453 ultraviolet-visible spectrophotometer,the affecting factors were studied on the kinetic processes in iodometry involved in the volatilization of iodine and the oxidation of iodide ion by dissolved oxygen,in particular such as the shape of the vessel,the volume of the solution tested,the concentration of KI and the temperature and the acidity of tested solution.The research shows that the volatilization of iodine corresponds to the kinetic model of the first order reaction while the oxidation of iodide ion by dissolved oxygen in acidic medium matches that of the pseudo zero order reaction.A series of experiments clearly illustrated and explained the importance of controlling the proper experiment condition in iodometry from a quantitative point of view.