Acid-base is prerequisite material for studying the hydrolysis of salts and buffer solutions. This material is still difficult to understand for students. This study aims to reveal the level of validity and practicality of electronic module based on structured inquiry containing three levels of chemical representation. This research was Research and Development (R&D) using Plomp’s development model. The research instrument was a validaty and practicality questioannair. The e-module was validated by 4 chemistry lectures and 2 chemistry teachers. The practicality test was carried out on 2 chemistry teachers and 65 students grade XI of Senior High School. The data were analyzed using the Kappa Cohen formula. The result of the study showed the developed e-modul had a very high level of validation ( k = 0.86). The results of practicalities also showed a very high level, k=0.90 response of teachers, and k= 0.88 response of students. The e-module was valid and practically for in acid-base learning in Senior High School.