1 Experiment 5 ACID BASE TITRATION OBJECTIVES • To demonstrate the basic laboratory technique of titration. • To learn how to calculate molarity based on titrations. • Determine the concentration of base. MATERIALS 50 mL buret Ring stand Utility clamp 10 mL pipet 10 mL graduate cylinder Phenolphthalein indicator 250 mL Erlenmeyer flask INTRODUCTION 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. Molarity (M) or molar concentration is a common unit for expressing the concentration of solutions. It is defined as the number of moles of solute per liter of solution (or millimoles of solute per milliliter of solution). ? = ????? ?? ?????? ?????? ?? ?????𝑖?? 𝑖? ?𝑖???? The concentration of a basic solution can be determined by titrating it with a volume of a standard acid solution (of known concentration) required to neutralize it. The purpose of the titration is the detection of the equivalence point, the point at which chemically equivalent amounts of the reactants have been mixed. The amount of reactants that have been mixed at the equivalence point depends on the stoichiometry of the reaction.