ProcedureThe synthesis of aspirin was started by mixing salicylic acid with acetic. Sulfuric acid was added to the mixture as a catalyst to start the reaction. The mixture was left to sit, allowing the chemicals to react. It was then chilled in an ice water bath, after which five mL of deionized water were then added to the mixture. The water was added slowly versus all at once because the water destroys any remaining acetic anhydride, releasing heat. If too much water were to be added at once, the mixture could boil over, causing a loss of product. The mixture was the put back into the water bath, and solid aspirin crystals began to form. The crystals were filtered using vacuum filtration, and were weighed once they were completely dry. Using the balanced equation for the reaction, the theoretical mass of aspirin was calculated. Then, using the mass of aspirin obtained, the percent yield of product was calculated.A Ferric Chloride Test and a Sodium Bicarbonate Test were then performed to determine thepurity of the aspirin synthesized. Each test was performed on the synthesized aspirin, salicylic acid, and stock aspirin. In performing the Ferric Chloride Test, less than 0.25 grams of each substance was mixed with ethanol, to which three drops of ferric chloride were then added. The purity of the substance was determined by whether or not the mixture turned purple from the presence of phenols. In performing the Sodium Bicarbonate Test, less than 0.25 grams of each substance were mixed with 1-2 mL of sodium bicarbonate. This test was used to determine the purity of the aspirin depending on whether or not CO2 was produced by the reaction. During the third part of the lab, the preparation of some flavoring esters, two mL of the carboxylic acid and 2 mL of the alcohol were mixed together. The mixtures were then placed in a hot bath of about 80° C (except for the reaction of salicylic acid and methyl alcohol, for which the boiling point of methyl alcohol is 65° C). After heating the mixtures in a hot water bath, thesolutions were poured into an evaporating dish, and one mL of sodium bicarbonate was added to each mixture. As a result, each ether produced a distinct smell.Results/ConclusionDuring the first part of the lab, the synthesis of aspirin, 0.92 grams of aspirin were synthesized. Based on the balanced equation for the reaction between salicylic acid and acetic anhydride, the theoretical yield was calculated to be 1.304 grams of aspirin. Based on these two quantities, the percent yield of the synthesized aspirin was calculated to 70.55%. While testing the purity of the synthesized aspirin, the salicylic acid turned purple due to the presence of phenols during the Ferric Chloride Test, the stock aspirin showed no visible change in the presence of the ferric chloride, and the synthesized aspirin turned a very light purple, which shows that it was relatively pure, but not completely. During the Sodium Bicarbonate Test, the salicylic acid produceda salt, which is the reason for the change in solubility. Both the stock aspirin and the synthesized aspirin produced CO2, which proves that both substances are relatively pure. The Ferric Chloride Test was a better indication of how pure the synthesized aspirin is because the results of the test were more visible. During the third part of the lab, the first reaction is between salicylic acid and methyl alcohol. After the sodium bicarbonate is added, the solution emits a wintergreen fragrance. The second reaction is between propanoic acid and butanol ,and the solution has a banana-like smell. The third reaction is between 3-methyl-1-butanol and glacial acetic acid, and it also emits a banana-like smell when the sodium bicarbonate is added. This lab had several possible sources of error, such as weighing errors, the synthesized aspirin not being completely dried when it is weighed, and the temperature of the hot water bath being too high and causing some of the mixture to boil