Question 12
Formally, chalk or calcium carbonate is insoluble in water but a small amount of it is actually in equilibrium between a dissolved state in water and an insoluble phase: $\mathrm{CaCO_3(s)\rightleftharpoons Ca^{2+}(aq)\quad CO_3^{2-}(aq)}$ Which of the following will cause the dissolution of more $\mathrm{CaCO_3}$ in water?