Acid-base Titration Based on Students’ Ability Training of Problem Solving

Based on the problem-solving-oriented principle, there comes to a comprehensive design with an integration of experiment content and teaching process when doing the experiment of determining composition and content in mixed alkali, one part of the acid-base titration experiment. Started form the problem “how to get the accuracy results of the composition and content in the mixed alkali”, the composition in alkali sample is analyzed primarily at first, then according to the principle of double-tracer technique, the rule of how phenolphthalein amount influences the color of the primary endpoint is studied by spectrophotometry method. At last, the composition and content in mixed alkali sample are measured with the controlled color as a reference of the end-point color. Compared to other common verification experiment, this experiment is substantial in content, comprehensive, challenging and interesting. In addition, the teaching process of this experiment with the exploring problem as the clue and solving problem as the goal is designed throughout “before, in and after lessons” parts. This teaching design emphasizes the training of students’ problem solving ability and their knowledge migration and application skill.