Answer to Question #165301 in Organic Chemistry for Collins

Question

 The following is a description of an experiment in which ethyl benzoate is hydrolyzed. 5cm (0.03 moles) of ethyl benzoate   are mixed with 30cm³  of 2M NaOH solution and heated under reflux for about 15minutes until all the oily drops have disappeared.  The flask is then filled for fractional distillation and the mixture distilled until the boiling point reaches 75⁰ to give a distillate "A".     

 The content of the flask is allowed to cool and then slowly acidified with concentrated hydrochloric acid when a precipitate "B" separates. This precipitate is purified by recrystallization from water.

       a. What is the liquid A?

b. Give the chemical test and its results which would support your answer in (a.)

Answer 1

A) Benzoic acid

B) First, add some NaOH to dissolve the benzoic acid. Then ad the solution of FeCl₃ and observe a formation of pinkish-yellow precipitate of Fe-Benzoic acid: