CH 202
Exam #2
March 1, 2000

Name ______________________________

Page

Points

1

______(16)

2

______(24)

3

______(12)

4

______(12)

5

______(10)

6

______(14)

7

______(12)

Total

______(100)

1. True or False (Circle Tor F) (6 pts, 2 pts each)

(i) According to Huckel's rule, a molecule with (4n+2) πelectrons will be aromatic.TF

(ii) Benzene is more reactive toward catalytic hydrogenation than is cyclohexane.TF

(iii) The two Kekule forms (resonance structures) of benzene are in equilibrium with each other.TF

2. Label the following planar molecules as aromatic or nonaromatic. (10 pts)

N

H

1

3. Show a detailed arrow pushing mechanism for the following reaction. Show at least 2 more resonance
structures for the intermediate arenium ion. (10 pts)

Br2/FeBr3

Br

4. Fill in the reagents necassary to carry out the following electrophilic aromatic substitutions. (9 pts)

Cl

NO2

O

5. Briefly but completely explain the following. Wherever possible, DRAW STRUCTURES to complete
your answer. Account for the difference in the acidity between A and B. (5 pts)

H

H

A

K= 10-40
a

Ka= 10-16

H

H

B

2

8. Consider the IR and NMR spectra below. The compound in question has the molecular formula
C8H10O.

a. (2 pts)What does the IR spectrum tell you about the oxygen atom?

b. (2 pts)How many substituents are present on the ring? __________

c. (6 pts)Draw the structure of the compound. CIRCLE YOUR FINAL ANSWER.

3