


Study with the several resources on Docsity
Earn points by helping other students or get them with a premium plan
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Community
Ask the community for help and clear up your study doubts
Discover the best universities in your country according to Docsity users
Free resources
Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors
Questions from an organic chemistry exam held in spring 2001. The exam covers topics such as separation methods, tlc, distillation, acid-base reactions in nonaqueous solvents, and the wittig reaction. Students are required to answer questions related to filling in missing parts, changing conditions for tlc, defining boiling points, and understanding reaction mechanisms.
Typology: Exams
1 / 4
This page cannot be seen from the preview
Don't miss anything!
* For all answers, use only the space provided in the question.
* You have 50 min. * We believe that questions with a mark are more difficult than others.
* At the end of the test, there are NMR correlation tables.
1. Separation methods:
a. Extraction:
(6 pts) fill in the missing parts (marked by *).
(5 pts ) How many extraction steps (washes) are needed to extract at least 99.8% of compound X from solvent A to B if it is 4 times more soluble in B? Show work.
organic phase aqueousphase
aqueous phase
organic phase
(^) *
b. TLC: (5 pts) When you try to run (develop) a TLC for Caffeine with 1/ Methanol/CH 2 Cl 2 – it doesn’t run (by the end of the run, the spot is still on the “starting line”). What should you change to make it run?
c. Distillation:
(3 pts) Define Boiling Point.
(3 pts ) A compound boils at 145 ˚C but decomposes at 110 ˚C. How can you purify it by distillation?
2. Acetaminophen: p- aminophenol reacts with acetic anhydride to yield p- amidophenol acetate (acetaminophen). In the laboratory, you first dissolved the p- aminophenol in HCl, then heated the solution in hot water bath, and added basic buffer (sodium acetate) and acetic anhydride. a. (5 pts) Why did you have to add HCl in the first place? Please write the chemical reaction for this stage.
b. (10 pts) Why did you have to add sodium acetate before adding acetic anhydride?
c. (5 pts) Which atom is the nucleophile and which atom is the electrophile in this amidation reaction?
a. 1) (5 pts) What does Fourier Transformation (FT) do?
b. (15 pts) Propose a structure and assign hydrogens to peaks for each of the compounds whose spectrum is shown below: