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. Why do you use calcium chloride in this reaction?

2. Why is it necessary to add the sulfuric acid slowly in this experiment? Show pertinent equations.

3. How many products do you isolate from your reaction this week? Rationalize the relative yields for these products.

4. Referring to the recrystallization of the crude product,

a. why does the procedure ask you not to place the solution in an ice-bath?

b. why is high boiling-boiling petroleum ether used and not the low-boiling form?

c. what is petroleum ether?

d. why does the solution often turn brown or purple during the recrystallization?

5. A student has the following solvents available in his lab: tetrahydrofuran, ethanol and hexane. Which one should he use to run a Grignard reaction? Explain briefly.

6. Which of the following functional groups are not compatible with Grignard reagents? Explain briefly why and show pertinent equations if necessary.

a. Nitro

b. Amines

c. Thiol