1. Introduction
Hydrochloric Acid, HCl, is one of the primary components …show more content…
The neutralization capabilities of all four were evaluated using back titration. One 100 mL Erlenmeyer flask, four 50 mL Erlenmeyer flasks, and a tablet of commercial antacid were obtained. The antacid tablet tested was Alka-seltzer/Effervescent. First the tablet was crushed and dissolved in 100 mL of 0.15 M HCl solution in the 100 mL Erlenmeyer flask. CO2 (aq) is a common product that can act as a buffer during titration. Therefore CO2 was heated under the hood (which ensured that the inhalation of carbon dioxide was as minimal as possible), and excess CO2 gas was released. CO2 bubbles formed, but the solution was not allowed to boil. When the carbon dioxide bubbles ceased to form, the flask was removed from the heat and allowed to cool to room temperature. The solution was then distributed into the five 50 mL flasks using a 20 mL pipette so that each flask contained 20 mL of the HCl solution. Two drops of Phenolphthalein indicator, which changes color in the pH range of 8.3 to 10.0, were added to the solutions in each flask. A 100 mL volumetric burette was filled with 100 mL of NaOH, and back-titration was performed. The first trial was a rough estimate test to determine the approximate endpoint, and then the following 4 trials repeated the same technique with more accuracy. When the correct amount of base had been added to an acidic solution so that it was