Analysis Of Acetic Acid With Sodium Hydroxide

762 Words2 Pages

MATERIALS AND METHODS:
Before the acetic acid solution could be titrated with sodium hydroxide (NaOH), the actual concentration of NaOH needed to be determined. By way of standardization, the actual concentration of NaOH was established, to account for the fact that the solid is not pure and for its tendency to react with carbon dioxide in the air.

A 50 mL burette (±0.01 mL, Kimax) was rinsed thoroughly, twice with reverse osmosis water, and then twice with approximately 5 mL of ~0.25 M NaOH solution (Fisher Scientific, Certified ACS Pellets, S318-3). A 125 mL Erlenmeyer flask (Fischer) was obtained and 0.999 g of potassium hydrogen phthalate (KHP, C8H5KO4) (Acros Organics, 99+%, Code: 417955000, Lot: A0358893) was added. A precision balance …show more content…

Three drops of the indicator, phenolphthalein, was added to the flask containing the dissolved KHP. The burette was then filled with ~0.25 M NaOH, using a glass funnel, and a small amount was drained in order to remove the remaining air from the tip. The initial volume of the burette was recorded to the nearest hundredth milliliter. The flask was placed under the burette and slowly, the NaOH was drained into the KHP solution, with constant mixing. The burette continued to be drained until the KHP solution changed from a clear color, to a persistent light pink, indicating the end …show more content…

Exactly 10.00 mL of vinegar (Stop and Shop Distilled White Vinegar, All Natural, 5% Acidity) was added to a 125 mL Erlenmeyer flask, using a 50 mL burette. Three drops of phenolphthalein indicator were mixed into the flask. The initial volume of the burette containing the NaOH was recorded to the nearest hundredth milliliter. The flask containing the vinegar was placed under the 50 mL burette and slowly, the NaOH was drained into the flask, with constant mixing. The burette continued to be drained until the acetic acid solution changed from a clear color, to a persistent light pink, indicating the end point of the titration. The final volume of the burette was then recorded to the nearest hundredth milliliter and the difference between the initial and final volumes was calculated; 31.35 mL or 0.03135 L. This volume in liters was multiplied by the concentration of the NaOH solution, 0.2838 M to determine the number of moles of acetic acid solution. This value was then divided by the volume of acetic acid solution originally added to the flask, 10.00 mL or 0.01 L, to obtain the molarity of the acetic acid solution; 0.8903 M. This process was replicated exactly a second and third time. The second titration required 31.39 mL of NaOH to be added, resulting in an acetic acid molarity of 0.8915 M. The third titration required 31.44 mL of

Open Document