Meeting 8 Problem Set

ATTN: answers to the below questions are due at the start of your lab period; these answers should be part of your pre-lab write-up

1. Referring to the Grignard reaction, answer the following questions.

a. Why does the student have to exclude water during the reaction?

b. What is the function of the drying tube in the setup? How is it properly packed?

c. During the work-up, 10% sulfuric acid is added to the reaction mixture. Show pertinent equations.

d. A student uses a water bath to remove the solvent. What would he observe?

e. Why is it important to use high-boiling petroleum ether for the recrystallization?

2. Referring to the GC spectrum that has to be acquired for crude and the final product, answer the following questions. Most students will see at least two peaks in the spectrum. How can one determine which compound belongs to the desired product? What is the most likely source of the other peak?

3. Referring to the TLC part of the experiment, answer the following questions.

a. Assume that the following three solvents are given: hexane, ethyl acetate and methanol. Which single solvent would be most suitable for the TLC in order to accomplish a good separation between the product and the reactant?

b. How could you improve the separation using these solvents?

4. Why are ethers often used as solvents for Grignard reactions?

5. Why are two products in unequal quantity obtained in this reaction?

6. What is cis-Platin and what is it used for?