Title : Reaction of Carboxylic Acids
Objective : To Determine The Reaction of Carboxylic Acids
Procedure : As referred to Lab manual.
A. Salt Formation
|Compound |Solvent |Solubility |
|Benzoic Acid |Cold Water |Partially soluble |
|Benzoic Acid |10 % NaOH |Soluble |
B. Salt Hydrolysis
Sodium acetate solution changed the color of litmus from red to blue.
C. Reaction With Sodium Carbonate
Observation : A lot of gas bubbles was released.
Ethanol : Fruity smell Isopentanol : Fruity smell
1. Write an equation that accounts for the solubility of benzoic acid in aqueous base.
(C6H5)COOH + OH- → (C6H5)COO- + H2O
2. What would you expect to happen if a solution of sodium benzoate was acidified? Write an equation.
If a solution of sodium benzoate was acidified, Na in sodium benzoate solution will displaced by the H+ from the acid and thus producing benzoic acid.
(C6H5)COO-Na+ + H2O/H+ → (C6H5)COOH + Na+ + OH-
3. Use your answers to Questions 1 and 2 to explain how a water-insoluble organic acid might be freed of non-acidic impurities.
Water-insoluble organic acid can be freed of non-acidic impurities by adding strong base into it during fractional distillation. The water-insoluble organic acid will react with the strong to produce an ionic salt which is soluble in water. On the other hand, water-insoluble organic acid which are slightly soluble in water can be extracted by aqueous base from solution in an organic solvent. The fact that organic acid are weak acids and only partially dissociates in water will cause the acid to be freed of non-acidic impurities. The salt solutions are alkaline.