last updated Tuesday, October 28, 2008

Problem set  Meeting 12 

Announcement

1. Make sure that you turn in a hardcopy of your research paper by November 7, 2008 at 5 pm and the electronic version to turnitin.com as well (CourseID: 2312446, Passwd: Chem30CL for Fall 2008). Late reports will be deducted points (10% per day including the weekend). If you do not submit the report online by Monday November 10, 10 pm, you will receive a "zero" score for the paper. In addition, it will be reported to the Dean of Students. Any plagiarism, partial or full resubmission of a papers or/and other forms of cheating will result in a report to the Dean of Students as well. Make sure that you cite your sources and try to use your own words as much as possible. Here is a checklist what should be included into the report. If you have any questions, please contact your TA or instructor asap, and not an hour before the submission deadline.

3. The next quiz (=quiz 5) will be administered on November 4, 2008 at 11 am and will cover steps 3 of the Lidocaine project and the Grignard reaction. Make sure that you show up on time. Otherwise you will not be allowed to take the quiz.

...and now back to the chemistry....the homework questions

1. Referring to the Grignard reaction, answer the following questions. Show chemical equations when appropriate.

a. Why is it imperative to remove the water from the reaction? How is this accomplished?

b. It was mentioned in lecture that the magnesium turnings should be crushed a little before placing them in the flask. Why?

c. How does the experimenter know that the reaction initiated? What could he do if the reaction did not to start on its own?

d. It is also important that the bromobenzene solution is added at the proper rate. Explain briefly.

e. After the formation of the Grignard reagent is completed, first the solution is cooled and then added to dry ice. Which purpose does each step serve and which precaution should be taken here?

f. The organic layer is extracted with sodium hydroxide solution. Explain briefly why.

g. Afterwards, hydrochloric acid is added to the layer containing the target compound. What would the student observe here?

h. Why is it important the final product is thoroughly dried?