The active ingredient of the antacid is CaCO3 and so Sally chose titration with HCl as a method for analysis. What is the mass (in g) of the CaCO3 in the sample of antacid, if it is titrated by 21.2 mL of HCl solution with concentration of 0.1048 mol/L to reach the endpoint?

Answer 1

moles acid used = M x L.
Moles CaCO3 is 1/2 that because
CaCO3 + 2HCl ==> CaCl2 + H2O + CO2

moles CaCO3 = grams/molar mass.
You have moles and molar mass. Solve for grams.