Chapter 11 Testbank (Klein)- Draft 2
1. Which of the following are the products of a homolytic cleavage of a C-C bond of
ethane?
A) CH3
2
B) CH3+CH3
C) +CH2H3
H
D) CH3
2
2. Which of the following is the most stable radical?
A)
B)
C)
D)
E)
3. In the molecule shown below, determine which of the labeled bonds is expected
to have the lowest bond dissociation energy.
C
C
C
C
C
C
C
HH
CH3
H
H
H
H
H
H
H
H
H
A
B
CD
E
4. Use correct arrow formalism to show a homolytic bond cleavage of ethane to
produce two methyl radicals.
5. Rank the following radicals in order of decreasing stability (most stable to least
stable).
I II III IV
A) IV > I > II > III
B) III > I > II > IV
C) III > II > I > IV
D) III > IV > II > I
E) II > III > I > IV
6. Rank the following radicals in order of decreasing stability (most stable to least
stable).
7. Using correct arrow formalism, draw all the resonance structures for the radical
shown below.
8. Use correct arrow formalism to draw all the resonance structure for the radical
shown below.
9. Which of the labeled C-H bonds is the weakest?
Ha
Hd
Hc
Hb
He
A) Ha
B) Hb
C) Hc
D) Hd
E) He
10. What term most accurately describes the process shown below?
Br +HBr +
A) coupling
B) proton transfer
C) halogen abstraction
D) hydrogen abstraction
E) homolytic cleavage
11. Use correct arrow formalism to show the following radical process:
Br +HBr +
12. What term most accurately describes the process shown below?
+
A) hydrogen abstraction
B) halogen abstraction
C) homolytic cleavage
D) coupling
E) elimination
13. Use correct arrow formalism to show the following radical process:
+
14. What term most accurately describes the process shown below?
+Br
Br
A) coupling
B) hydrogen abstraction
C) halogen abstraction
D) homolytic cleavage
E) addition to a pi bond
15. Use correct arrow formalism to show the following radical process:
+Br
Br
16. What term most accurately describes the process shown below?
+
A) coupling
B) elimination
C) halogen abstraction
D) hydrogen abstraction
E) homolytic cleavage
17. Use correct arrow formalism to show the following radical process:
+
18. Which of the following is an example of termination?
+Br Br
A)
B)
O
O
heat O
O
+
C) +Br
Br
D) Br ++ HBr
E) None of the above
19. Which of the following is an example of initiation?
+Br
Br
A)
B)
O
O
heat
O
O
+
C) +Br
Br
D) Br ++ HBr
E) None of the above
20. A bromine radical can add to the pi bond of 2-methylpropene. Use correct arrow
formalism to show this process and the expected result.
21. Which of the following represents a propagation step in the chlorination of
methylene chloride (CH2Cl2)?
A)
+ Cl2CHCl3+ Cl
CHCl2
+ Cl CCl3+ HCl
CHCl3
C) + Cl2CH2Cl2+ Cl
CH2Cl
+ Cl CHCl3
CHCl2
B)
D)
22. Which of the following would you expect to function as an initiator at the lowest
temperature?
A) B) Cl2C) O
OD) O
O
O
O
23. Use correct arrow formalism to show the propagation steps in the chlorination of
propane to produce 2-chloropropane.
+Cl + HCl
H
24. Which of the following are possible termination steps in the chlorination of
methane?
A)
+ Cl2CH3Cl + Cl
CH3
+ Cl CH3+ HCl
CH4
C) + CH3CH3CH3
CH3
+ Cl CH3Cl
CH3
B)
D)
25. Which of the following is most reactive towards chlorination?
A) methane
B) chloromethane
C) dichloromethane
D) chloroform
E) ethane
26. Free radical chlorination of ethane can produce higher halogenation products
(dichlorinated, trichlorinated, etc…) in addition to chloroethane. How could the
production of higher halogenated products be minimized?
A) Use an excess of chlorine
B) Use an excess of ethane
C) Use equimolar chlorine and ethane
D) It is not possible to minimize the production of higher halogenated products
27. Which of the following shows the initiation step of monochlorination of methane?
I. Cl22 Cl
2 BrII. Br2
III. 2 Cl Cl2
IV. HOOH 2OH
A) I
B) II
C) III
D) IV
E) I and II
28. How many constitutional isomers are possible if propane is dichlorinated? Draw
them.
Chapter 11
29. Which of the following processes is responsible for the fact that free radical
bromination of methane is slower than free radical chlorination?
A) initiation
B) hydrogen abstraction
C) halogen abstraction
D) termination
E) entropy
30. Which of the following is the rate-determining step in the free-radical
bromination of methane?
Br22 Br
C
H
H H
H
+Br C
H
H
H
+ HBr
C
H
H
H
+ Br-Br C
H
H Br
H
+Br
C
H
H
H
C
H
H
H
C
H
H
H
C
H
H
H
+
A)
B)
C)
D)
31. Predict the major product obtained upon radical bromination of t-
butylcyclohexane.
A) 1-bromo-1-t-butylcyclohexane
B) 2-bromo-1-t-butylcyclohexane
C) 3-bromo-1-t-butylcyclohexane
D) 4-bromo-1-t-butylcyclohexane
E) (1-bromo-1,1-dimethyl)ethylcyclohexane
32. Cyclic compound A has molecular formula C5H10 and undergoes
monochlorination to yield only three different constitutional isomers. Identify
compound A and show the monochlorination products.
Cl Cl
Monochlorination productsA
33. Predict the major product of the following reaction:
h
Br2
A. Br
Br
Br
Br
B.
C.
D.
34. Predict the major product(s) of the following reaction:
h
Br2
A.
B.
C.
D.
Br
Br
Br
Br
35. Both compounds A and B have molecular formula C6H14. Monochlorination of
compound A results in formation of two constitutional isomers. Monochlorination of
compound B results in formation of four constitutional isomers. Identify compounds A
and B, and show the products of each monochlorination.
Cl
Cl
Compound A Monochlorination products of compound A
36. Which of the following correctly describes the nature of the transition state of the
rate-determining step of the free-radical bromination of methane?
A) the transition state resembles the reactants more than the products
B) the transition state resembles the products more than the reactants
C) the transition state equally resembles products and reactants
37. Predict the major product(s) of the following reaction.
h
Br2
38. Predict the major product(s) of the following reaction.
h
Br2
A) R-3-bromo-3-ethylbutane
B) S-3-bromo-3-ethylbutane
C) R-3-bromo-3-methylpentane
D) S-3-bromo-3-methylpentane
E) 3-bromo-3-methylpentane
39. Predict the major product(s) of the following reaction.
h
Br2
40. Predict the major product(s) of the following reaction.
h
Br2
Br
Br
Br
Br
Br
III III IV V
A) I
B) II and IV
C) III and V
D) IV and I
E) V
Chapter 11