<![CDATA[Chemical equilibrium is a conceptually demanding topic because it requires students to coordinate dynamic, symbolic, particulate, and macroscopic explanations. Persistent alternative conceptions may remain hidden when assessment relies only on conventional multiple-choice tests. This study diagnosed students' misconceptions about chemical equilibrium and examined the effectiveness of remedial instruction based on the Elicit, Confront, Identify, Resolve, and Reinforce (ECIRR) learning model. A pre-experimental one-group pretest-posttest design was implemented with 35 Grade XI science students at a public senior high school in Malang, Indonesia. Data were collected using a 14-item two-tier diagnostic test and an ECIRR-based remedial learning scenario. Expert validation indicated that the diagnostic test was very valid (82.14%) and the ECIRR scenario was very valid (92.40%), while the diagnostic instrument showed good internal consistency (Cronbach's alpha = 0.845). The pretest identified misconceptions related to the equality of reactant and product concentrations, dynamic equilibrium, concentration-time graphs, temperature and pressure perturbations, and catalyst effects. After five ECIRR-based remedial meetings, students' mean diagnostic score increased from 1.51 to 4.97 out of 14. Because the Shapiro-Wilk test indicated non-normality for both pretest and posttest data, a Wilcoxon signed-rank test was applied and showed a significant improvement (Z = -4.677, p < 0.001), with a large effect size (r = 0.79). The findings suggest that ECIRR can support conceptual restructuring by making students' initial conceptions explicit, generating cognitive conflict, and reinforcing scientifically acceptable explanations. However, the low absolute posttest score indicates that misconception remediation in chemical equilibrium requires sustained, multi-representational, and diagnostically informed instruction.]]>
