One brand of extra-strength antacid tablets contains 750 mg of calcium carbonate (100 g/mol) in each tablet. Stomach acid is essentially a hydrochloric acid solution. Is so much calcium carbonate really needed to neutralize stomach acid? Calculate the volume of stomach acid with a pH of 1.0 that one of these tablets could neutralize, and compare that value with the normal volume of stomach fluid, which usually is about 100 mL. One tablet can neutralize ________ mL of stomach acid at a pH of 1.0.

Question

Quizplus · Accepted Answer

One tablet contains 750 mg of calcium carbonate, which is 0.0075 mol. The pH of 1.0 corresponds to a hydrogen ion concentration of 0.1 M. The reaction between calcium carbonate and hydrochloric acid is: CaCO3 + 2HCl → CaCl2 + CO2 + H2O. Thus, 0.0075 mol of CaCO3 can neutralize 0.015 mol of HCl. Therefore, the volume of stomach acid that can be neutralized is 0.015 mol / 0.1 M = 0.15 L or 150 mL.

One Brand of Extra-Strength Antacid Tablets Contains 750 Mg of Calcium