Question

9. In this laboratory experiment, you use excess carboxylic acid (2.4 equivalents). Therefore, when the reaction is complete, you will have some carboxylic acid along with your ester as the product. Answer the following questions: (a) How was this excess carboxylic acid removed from your ester product? To answer this question, answer the two parts below. (i) Draw the reaction that allows for the excess carboxylic acid to be removed below. You must show the starting materials of the reaction, the arrow pushing mechanism that leads to product formation, and the products of the reaction. Hint: The reagent in this reaction is sodium bicarbonate. (ii) Explain how the reaction above removes the excess carboxylic acid. Discuss where the carboxylic acid goes and why? Write in complete sentences.

Answer 1

Darboxylic (Natcoal Weled acids react with sodium bicarbonate to form a salt, Carbon dioxide and a o CooH + NaHCO3 + HC ty ca cata An acid-base extraction can be used to extract Cao boxylic acids from the organic laser inte the aqueous layer. When Nahlo reacts with benzoic acid the byproduct Carbonic acid (20) can decom pase to water and carbon dioxide zes When shaking an acidic Solution with sodium bicarbonate in a seperatory funnel, care should be taken to swird gently and Vent more frequently to release pressure from gas. An example of a reaction that aften uses sodium (bicarbonate wash in the wook-up is a fischer estedification Deaction the residual "Carbarylic acid can be removed from the desired ester Product using an acid-bat extaction in a seperatory funnel. A wash. Wilh Sodium bicarbonate. conuests benzoic acid into its more water-solublescidium benzoate form extracting into its aqueus layer Adizionally, the sodium bicasbonate neutralizes the catalytic acid in this reaction