A mixture containing benzoic acid (C₆H₅CO₂H) and naphthalene (C₁₀H₈) is dissolved in…
CHEMISTRY · Multi-part · AP · Chemistry · Acids and Bases · Acids and Bases
Problem
A mixture containing benzoic acid (C₆H₅CO₂H) and naphthalene (C₁₀H₈) is dissolved in 50 mL of diethyl ether. A chemist separates the two substances by vigorously shaking the ether solution with an equal volume of aqueous NaOH and then isolating each phase.
Answer the following questions about the process.
(a) Describe the predominant intermolecular forces that enable benzoic acid and naphthalene to dissolve in diethyl ether but limit their solubility in liquid water.
(b) Write a balanced chemical equation for the reaction that occurs when benzoic acid is contacted with aqueous NaOH. Explain how this reaction alters the relative solubility of benzoic acid in the two liquid phases present.
(c) After the aqueous layer is separated, the chemist slowly adds 6 M HCl until the pH reaches 2 and then cools the mixture in an ice bath. Predict the macroscopic changes that will be observed and explain the molecular events responsible for those observations.