Complexometric Titration of Aluminum and Magnesium Ions in Commercial Antacids. An Experiment for General and Analytical Chemistry Laboratories

Abstract

Few chemical experiments use the reagents from consumer products. Student interest in chemistry usually suffers from the lack of relevance to their daily lives. Ultimately this leads to insufficient student chemical problem-solving ability. A novel experiment for determining metallic ions in commercial antacids is described. This experiment is developed with three independent protocols based on complexometric direct and back titrations containing the concepts and usages of blocking, masking, buffer controls and metallic indicators. The three protocols involve determining the total aluminum and magnesium ion contents and individual ion content. This approach is different from determining the acid-neutralizing power of anions in antacids using acid–base titration. Using statistical analyses, student and instructor data indicated good results. Student comments were positive. Thus, this experiment is feasible for general chemistry and introductory analytical chemistry laboratories.