The Dissolution of Magnesium Oxide in Dilute Sulfuric Acid

The kinetics of dissolution of sintered magnesium oxide pellets in dilute sulfuric acid at 4.00 and 25.00 °C have been investigated using the rotating disc technique. The rate of depletion of hydrogen ions in the bulk solution is found to be controlled by both transport through the diffusion layer and chemical reaction with the oxide surface. The chemical reaction occurring at the oxide surface has an activation energy of 13 kcal mol −1 . The diffusion coefficients for hydrogen ion in dilute sulfuric acid at the two temperatures of interest have been calculated. These coefficients yield an activation energy of 3.6 kcal mol −1 for the diffusion of hydrogen ions to the oxide surface.