(Figure ). The solutions with sulfuric and phosphoric acid showed higher pH values (3.2 and 3.5) because the acids were not completely dissociated due to their lower acid strength (pK A2 = 1.92 for HSO - 4 and pK A1 = 2.15 for H 3 PO 4 and even weaker dissociations constants for the further deprotonation steps). After CAC addition at t = 0 min, the pH increases to approximately 5.8 with H 3 PO 4 , while it increases to around 4.6 for all other acids. In all cases, the conductivity drops to <0.1 mS/cm in the presence of the acids. With HClO 4 , HNO 3 , and H 2 SO 4 , the pH and conductivity trends are similar to the experiment with HCl. For each experiment, the steep increase in conductivity corresponds to the time when the pH reaches a value of 9, as indicated by the grey vertical dotted lines in Figure . As a consequence of these similarities to hydrochloric acid, we conclude that the onset of initial CA dissolution is also inhibited by the presence of HClO 4 , HNO 3 , and H 2 SO 4 .