Antacid Tablet: How Much Stomach Acid Can It Neutralize?

Antacids are medications used to neutralize stomach acid and alleviate symptoms of acid reflux, heartburn, and indigestion. One common reaction that occurs between an antacid and stomach acid involves Mg(OH)2 and HCl.

The balanced chemical equation for this reaction is Mg(OH)2(aq.) + 2HCl(aq.) --> MgCl2(aq.) + 2H2O(l).

To calculate the amount of stomach acid that can be neutralized by a given amount of Mg(OH)2 in an antacid tablet, we can use the molar ratio between HCl and Mg(OH)2. From the equation, we know that n(HCl)/n(Mg(OH)2) = 2/1.

Using the formula n = m/M, where n is the number of moles, m is the mass, and M is the molar mass, we can calculate the number of moles of Mg(OH)2 in the tablet. Given that the tablet contains 0.231g of Mg(OH)2 with a molar mass of 58.326 g mol^-1, we can find that n(Mg(OH)2) = 0.231g / 58.326 g mol^-1.

Next, we can determine the volume of stomach acid (HCl) that can be neutralized by the antacid tablet. Since the concentration of HCl is 0.035 mole dm^-3, we can use the formula c = n/V rearranged to n = c*V to find the number of moles of HCl. Then, using the molar ratio from the balanced equation, n(HCl) = 2 * n(Mg(OH)2).

Finally, we can calculate the volume of HCl by rearranging the formula to V(HCl) = 2 * m(Mg(OH)2) / (M(Mg(OH)2) * c(HCl)). Substituting the values, we get V(HCl) = 0.226 dm^3, which is equivalent to 226 mL.

Therefore, the antacid tablet containing 0.231g Mg(OH)2 can neutralize 226 mL of stomach acid (assumed to be 0.035 M HCl).