Abstract: A well-designed experiment allows students to better understand chemical principles through observable phenomena. This study investigates the reaction between potassium permanganate and potassium bromide under two different conditions: identical setups as found in standard textbooks and varying pH ranges. The results indicate that potassium bromide reduces potassium permanganate in two distinct steps in the pH range 1.95–0.98, with the reduction products being influenced by the pH of the solution. The critical pH for the spontaneous occurrence of the second step is 1.21, which is close to the theoretical value of 1.36. Based on these findings, two recommendations are provided to further refine the experimental design by verifying the impact of acidity on reaction rates.

Key words: Redox reaction, Potassium permanganate, Potassium bromide, Stepwise reduction, Acidity