same total acid concentration, the initial pH of the weak acid is less acid than the one of the strong acid; however, the maximum amount of which can be dissolved is approximately the same. This is because in the final state, the pH is larger than the pKa, so that the weak acid is almost completely dissociated, yielding in the end as many ions as the strong acid to "dissolve" the calcium carbonate. The calculation in the case of phosphoric acid (which is the most widely used for domestic applications) is more complicated since the concentrations of the four dissociation states corresponding to this acid must be calculated together with [], [], [], [] and []. The system may be reduced to a seventh degree equation for [] the numerical solution of which gives {| class="wikitable" |- ! width="160" |[A] (mol/L) | 1 | 10−1 | 10−2 | 10−3 | 10−4 | 10−5 | 10−6 | 10−7 | 10−10 |- ! width="160" |Initial pH | 1.08||1.62||2.25||3.05||4.01||5.00||5.97||6.74||7.00 |- ! width="160" |Final pH | 6.71||7.17||7.63||8.06||8.24||8.26||8.26||8.26||8.27 |- ! width="160" |Dissolved (g/L of acid) | 62.0||7.39||0.874||0.123||0.0536||0.0477||0.0471||0.0471||0.0470 |} where [A] = is the total acid concentration. Thus phosphoric acid is more efficient than a monoacid since at the final almost neutral pH, the second dissociated state concentration [] is not negligible (see phosphoric acid). See also Cuttlebone Cuttlefish Gesso Limescale Marble Ocean acidification Whiting event List of climate engineering topics Lysocline References External links ATC codes: and The British Calcium Carbonate Association – What is calcium carbonate CDC – NIOSH Pocket Guide to Chemical Hazards – Calcium Carbonate Calcium compounds Carbonates Limestone Phosphate binders Excipients Antacids Food stabilizers E-number additives