Visualization-Guided Teaching of Organic Acid Acidity via Computational Chemistry: Bridging Electronic Structure and Acid–Base Reasoning

Abstract

Understanding organic acid acidity can be challenging for undergraduates because conventional instruction often emphasizes qualitative rules and memorized pKa trends. This activity uses computational molecular visualizations to help students develop evidence-based reasoning (EBR) through cognitive conflict and guided inquiry. Students examine three contexts: the apparent discrepancy between carbonic acid’s reported pKa and intrinsic acidity, the complementary roles of reactant and conjugate-base electronic properties, and limitations of relating aromatic delocalization directly to acidity. Electrostatic potential, O–H bond strength, conjugate-base stabilization, and aromaticity-related visualizations are used as complementary evidence. The activity was implemented across two undergraduate cohorts (total N = 78), with diagnostic scores increasing from 5.9/15 to 10.7/15 (t(77) = 12.24, Cohen’s d = 1.37, p < 0.001). Student feedback indicated that molecular visualization and multiple sources of evidence supported their interpretation of acidity trends. Open-access computational and instructional materials are provided to facilitate classroom implementation.