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. Water has a detrimental effect in this reaction. Which precautions shoudl be taken to minimize its presence during the reaction?

2. How many mL of Grignard reagent (1.4 M MeMgBr) do you require in theory? Show your calculations.

3. During the work-up, a student is asked to add 10% sulfuric acid to the reaction mixture. Which precautions have to be taken in this step? Show pertinent equations.

4. Ethers often used as solvents for Grignard reactions. Rationalize this choice.

5. Referring to the recrystallization of the crude product, answer the following questions.

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

b. A student uses low-boiling petroleum ether as solvent. What would he observe?

6. Why are alkyl bromides more reactive than aryl bromides?

7. Why is it important to have Mg-metal of 'good quality'?