last updated Tuesday, May 09, 2006

Problem set  Meeting 12 

Announcement

The instructor will offer an in-lab demonstration of the Grignard setup on Wednesday May 10, 2006 at 4:00 pm in YH6086.

The final version of the paper is due on May 12, 2006 at 5 pm in YH3077E. Make sure that you turn it in online by May 15, 2006 at 10 pm.

Questions

1. Referring to the Grignard reaction, answer the following questions. Show chemical equations when appropriate.
 
a. Many metals are coated with an oxide layer on the surface. Why does this pose a problem for the reaction and how does the experimenter take care of this issue?

b. In which way is the water minimized in the reaction? 

c. A student prepares his glassware properly, yet the reaction does not initiate upon addition of the the bromobenzene solution. What should he do to solve the problem? (Hint: Praying is not the answer here! :-)) How does he know that the reaction initiated ?

d. The bromobenzene/diethyl ether solution is added slowly during the reaction. Why?

e. What is the function of the dry ice in the reaction? Why is it unwise to weight the dry ice significantly before it is needed?

f. Before adding the sulfuric acid during the work-up, "chipped ice" is added. Why?

g. How is the product isolated from the reaction mixture?

h. Why is it important to dry the product thoroughly?