Abstract: Konovalov's rule, serving as the fundamental principle for phase equilibrium in completely miscible binary liquid systems, represents both the starting point for complex phase diagram analysis and a persistent challenge in physical chemistry education. This study elucidates Konovalov's rule through essential physical mechanisms by employing basic physicochemical concepts, particularly the “chemical potential” framework, combined with thermodynamic theory and mathematical extremum analysis. The approach provides fundamental insights into the physical basis for phase classification in different regions of phase diagrams. Such theoretical analysis helps students overcome conceptual barriers in understanding phase diagrams while offering pedagogical guidance for interpreting these diagrams through chemical potential perspectives. The methodology presented holds significant implications for instructional design in materials science and chemical engineering education, particularly in phase diagram-related coursework.

Key words: Phase equilibrium, Konovalov's rule, chemical potential, phase diagram