Saifatun Nur Hafidzah Fida and Rinaningsih Rinaningsih 2025. Development of Diagnostic Test Instruments as Placement Tests to Determine Students’ Cognitive Learning Levels on Acid-Base Material. Journal of Educational Chemistry (JEC). 7, 2 (Dec. 2025), 101–108. DOI:https://doi.org/10.21580/jec.2025.7.2.27138.