Chemical Reactions Applied to Qualitative Analysis

The course Chemical Reactions Applied to Qualitative Analysis covers highly sensitive transformations that produce visually observable results, with emphasis on chemical equilibrium control and the reaction medium (temperature, concentration, pH) to direct precipitation, ion speciation, and test selectivity.

Among the fundamentals explored are classical precipitation, formation of poorly dissociated species, and electron transfer reactions, using the Solubility Product (Ksp) to predict precipitation and the common ion effect to optimize separations. The use of buffer solutions maintains controlled pH, ensuring selective precipitation of cation groups and avoiding co-precipitation of interferents.

When investigating unknown samples, the analyst follows a systematic route, starting with preliminary observations (color, pH) and gradual sample dissolution (water, dilute/concentrated acids, aqua regia). The course also goes deeper into complexation reactions (confirmation and masking of cations) and redox (dissolution of alloys/ores and visual identification of elements by changes in oxidation state), ensuring high analytical precision.