Titration Is An Analytical Method Used

Titration is an analytical method used to determine the exact amount of a substance by reacting that substance with a known amount of another substance. The completed reaction of a titration is usually indicated by a color change or an electrical measurement. An acid/base neutralization reaction will yield salt and water. In an acid-base titration, the neutralization reaction between the acid and base can be measured with either a color indicator or a pH meter.
Acid + Base  Salt + Water
In this experiment, a phenolphthalein color indicator will be used. Phenolphthalein is colorless in acidic solutions and pink in basic solutions. Phenolphthalein is also used in forensic crime scene analysis to detect the presence of blood, Kastle-Meyer test. In the Kastle-Meyer test, hemoglobin catalyzes the oxidation of the colorless form of phenolphthalein to its bright pink form.
Four lab periods assigned for this experiment. In part I you will prepare an acid (HCl) solution and a base
(NaOH) solution. These solutions will be used for all four periods so it is important to keep these solutions. These solutions will be titrated against each other to obtain a base/acid ratio. In part II you will find the normality of the base solution by titrating it against a solid acid standard. The normality of the acid can be calculated from the normality of the base and the base/acid ratio from part I. In part III the base will be titrated against an unknown acid to find the equivalent weight of the acid. In part IV the equivalent weight of an unknown base will be determined by reacting the unknown base with an excess of HCl and “back-titrating” the left-over acid with NaOH.