Acids and bases react together to form salt and water. When acids and bases react together and
use each other up completely, we are left with a neutral product.
The reaction between acids and bases is called neutralization. Neutralization is a kind of double
displacement reaction. Write the balanced chemical equation for the reaction between
hydrochloric acid and sodium hydroxide.
Comparison of Antacids
Antacids neutralize excess acids in the stomach. They do not generally use up all the acid in the
stomach, but they use up some of the acid and ease the discomfort.
I wonder which antacid neutralizes the most acid. That could be pretty useful info! Follow
the procedure below to compare three antacids.
1. Set up a buret on a stand. Fill the buret with 0.5M HCl. Record the initial volume of acid in
2. Measure the mass of an antacid tablet. Crush it and place it in a beaker.
3. Add 3 drops of bromthymol blue (BTB) to the antacid in the beaker and place beaker on a
piece of white paper. Recall that BTB turns yellow in acid.
4. As you add acid to the antacid, the two will react. When all of the antacid has reacted,
adding more acid will make the contents of the beaker acid. The pH indicator will then
make a permanent colour change. Add acid from the buret to the antacid mixture. Swirl to
mix. Continue to add acid until the pink colour has just disappeared.
5. Record the final volume of the acid. Determine the amount of acid neutralized by the
6. Repeat for two other types of antacids.
Mass of Final Initial Volume of Volume of Acid
Antacid Volume of Volume of Acid Neutralized per
Tab Acid Acid Neutralized g of antacid
(g) (mL) (mL) (mL) (mL/g)
Which is the best antacid? Why?