Why and how can titration be used to determine the concentration of anything?
Concentration is molarity. By carefully adding a substance with a known molarity and known volume to something with an unknown molarity and known volume, it is possible to figure out the Molarity of the the unknown with the following equation: (M1)(V1) = (M2)(V2). In order to know how much of the known to add, put phenolphthalein in the unknown, it turns colorless in acidic solutions and pink in basic solutions. The following picture shows the set up of titration.
To determine the concentration of an antacid tablet composed of magnesium bicarbonate (which is a base) you have to use an acid such as Hydrochloric Acid. Now based on my understanding of Titration and a little help from my sources, follow the steps to titrate Magnesium bicarbonate.
1. Clean, rinse, and fill a buret with HCl solution. Record the molarity of the HCl and the initial HCl volume reading from the buret .
2. Weigh the antacid tablet the and record the mass.
3. Transfer it to a clean 250 mL Erlenmeyer flask.
4. Add distilled water to the flask and swirl the flask to help dissolve the antacid. Make sure to dissolve it completely.
5. Add 3 – 4 drops of phenolphthalein indicator to the flask, and titrate the base solution to a phenolphthalein endpoint. Record the final HCl volume (+0.02 mL).
6. Repeat this analysis on two other brands of antacid tablets.