During lab you measured the pH of common household items. Write net Brønsted equations that show the acidic or basic nature of the following substances, given the pH. For polyprotic acids, only show one proton transfer. Remember that spectator ions are not included. (Use the lowest possible coefficients. Omit states-of-matter in your answer.)
(a) tums antacid (calcium carbonate) with a pH = 8.50
(b) lithium hydrogensulfite with a pH = 4.40
(c) milk (lactic acid = HC3H5O3) with a pH = 6.60