Question

The active ingredient in this antacid is CaCO3 which is results in the following reaction: CaCO3+ 2HCl → CaCl2+ H2CO3. Because this is a 2:1 reaction how will that affect the number of moles you calculated for the base in the antacid?

Answer 1

Antacid is used when we feel acidity in our stomach. We know we have strong acid HCl as stomach juice. When the amount of this acid increases due to indigestion of food or empty stomach for a longer time, we feel burning in our stomach.

So to reduce this burning we take Antacid, which is a basic solution of basic salt CaCO3. This salt reacts with the strong acid HCl, and converts into an weak acid H2CO3, which further breaks down to form H2O and releases CO2 gas.

The actual reaction is-

CaCO3+ 2HCl → CaCl2+ H2CO3

H2CO3 → H2O + CO2

Now for each mole of acid (lets say 1 mole), we required half the moles of CaCO3 (i.e 1/2 moles) for complete neutralization. i.e lets say from the pH of our stomach juice , we calculated the concentration of H+ ion or HCl and know the number of moles of HCl present (lets say x moles), then we have to take corresponding antacid solution, where the number of moles of CaCO3 is x/2.