Balanced Net Ionic Equations with Antacids:

Question

Write a balanced net ionic equation for the neutralization of hydrochloric acid with each of the antacids.

Alka-Seltzer:

Equate:

Gaviscon:

Maalox (tablet):

Milk of Magnesia:

Rolaids:

Answer 1

In order to tackle this question, we first need to determine the active chemical ingredient in each antacid. Here's what they are:

Alka-Seltzer: sodium bicarbonate NaHCO3

Equate: calcium carbonate CaCO3

Gaviscon: aluminum hydroxide Al(OH)3

Maalox (tablet): calcium carbonate CaCO3

Milk of Magnesia: magnesium hydroxide Mg(OH)2

Rolaids: calcium carbonate CaCO3

Each of these are weak bases when dissolved in water, meaning they will react with any strong acid such as hydrochloric acid (HCl). The net ionic equation will contain all of the reactant and product ions which are consumed and formed during the reaction.

Chemical equation:

HCl + NaHCO₃ -> NaCl + H₂O + CO₂

Total ionic equation:

H⁺ + Cl^- + Na⁺ + HCO₃^- -> Na⁺ + Cl^- + H₂O + CO₂

Cancelling out the ions which are on both sides of the total ion equation gives the net ionic equation:

H⁺ + Cl^- + Na⁺ + HCO₃^- -> Na⁺ + Cl^- + H₂O + CO₂

H⁺ + HCO₃^- -> H₂O + CO₂

The rest of the antacids with carbonate salts can easily be worked out from here.

For Gaviscon, a metal hydroxide antacid the balanced chemical equation is:

3HCl + Al(OH)₃ -> AlCl₃ + 3H₂O

Total ionic equation:

3H⁺ + 3Cl^- + Al3⁺ + 3OH- -> Al3⁺ + 3Cl^- + 3H₂O

Cancelling out the ions which are on both sides of the total ion equation gives the net ionic equation:

3H⁺ + 3Cl^- + Al3⁺ + 3OH- -> Al3⁺ + 3Cl^- + 3H₂O

3H⁺ + 3OH^- -> 3H₂O

This is a standard acid base reaction. The other antacids with metal hydroxides can be solved using these same steps.