摘要：This research is aimed at developing a product in the form of a Chemical Equilibrium Misconception Detecting Instrument or IPMKK for Grade XI senior high school students to investigate the quality of IPMKK based on the expert judgment using the Focus Group Discussion (FGD), continued with an analysis using the three-parameter Item Response Theory (IRT) and the feasibility of IPMKK imple-mentation in the field. This research was a research and development study using the procedural model, adapted from Borg & Gall model. The development of the product began by conducting the needs assessment and the literature review to choose a chemical equilibrium and multiple choice test with half-open reason as the instrument to be developed. Findings suggest that this research succeeds in developing a Chemical Equilibrium Misconception Detecting Instrument (IPMKK) for Grade XI senior high school students. The feasibility test suggests that Senior High School chemistry teachers do not have difficulty in implementing the instrument and can conduct the data analysis easily. The implementation of the instrument in the DIY province detected that there was M1i-1 chemistry misconception by 13.84% Mi-1 and Mi-2 by 18.43%.Keywords: instrument development, misconception, chemical equilibrium
