CHM 2210 Problem Set 8
Due: November 7th, 2008
S. A. Miller
KEY
Name: _______________________
student#
score/20
Multiple Choice (1 point each)
letter
Br
Br
(1) What is the IUPAC name of the following compound?
(A) 1,1-dibromo-3-tert-butylcyclohexane
(B) 3-tert-butyl-1,1-dibromocyclohexane
(C) 3,3-dibromo-1-tert-butylcyclohexane
(D) 1,1-dibromo-3-isopropylcyclohexane
(2) Which of the following alkenes undergoes allylic bromination to form a single
monobrominated product?
(A)
(B)
(C)
(D)
(E)
A
(3) How many different monobromination products can be formed in the allylic
bromination of the following molecule? (Count stereoisomers separately.)
(A) 1 (B) 2 (C) 3 (D) 4 (E) 5 (F) 6 (G) 7 (H) 8 (I) 9 (J) 10
H
Br
E
Br
Br
Br
Br
Br
Br
Br
(4) Which of the following is an unlikely product of free radical bromination?
Br
(A)
(B)
(C)
(D)
Br
Br
Br
C
(5) What is the best choice of reagent to perform the following transformation?
Br
(A) Br2, H2O
(B) Br2, CH2Cl2
(C) HBr, peroxides (D) HBr
(6) What is the IUPAC name of the following compound?
(A) (1E,3E)-1-bromo-2-methyl-1,3-pentadiene
Br
(B) (1Z,3E)-1-bromo-2-methyl-1,3-pentadiene
(C) (1Z,3Z)-1-bromo-2-methyl-1,3-pentadiene
(D) (1E,3E)-5-bromo-4-methyl-2,4-pentadiene
(7) What is the fewest number of lines required to draw the line-angle structure
of 1-chloro-3-methylcyclobutane?
(A) 1 (B) 2 (C) 3 (D) 4 (E) 5 (F) 6 (G) 7 (H) 8 (I) 9 (J) 10
C
A
CH3
F
Cl
Br
(8) How many different monobromination products can be formed in the radical
bromination of neohexane? (Count stereoisomers separately.)
Br
(A) 1 (B) 2 (C) 3 (D) 4 (E) 5 (F) 6 (G) 7 (H) 8 (I) 9 (J) 10
Br
Br
(9) Compund X has formula C5H12 and gives only one monochlorination product. What is X?
A) 2-methylbutane B) 3-methylbutane
C) 2,2-dimethylbutane C) 2,2-dimethylpropane
D) cyclopentane
E) cyclohexane
F) methycyclobutane X
Cl
D
(10) Calculate ΔH° for the following reaction: (CH3)3CH + Cl2 --> (CH3)3CCl + HCl
(A) 0 kcal/mol (B) -18 kcal/mol (C) -32 kcal/mol (D) -40 kcal/mol (E) -44 kcal/mol
C
C
From Appendix 3: 97+59-85-103 = -32 kcal/mol
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CHM 2210 Problem Set 8
ΔH = Cl-Cl + C-H (2°) - [Cl-C (2°) + H-Cl]
= +59 + 99 - [85 + 103] = -30 kcal/mol
student#
letter
(11) What is the ΔH (in kcal/mol) for the radical monochlorination of cycloctane with Cl2?
See Appendix 3.
(A) -30 (B) -20 (C) -10 (D) 0 (E) 10 (F) 20 (G) 30
(12) What is the ΔH (in kcal/mol) for the ionic monochlorination of cycloctane with Cl2? See
Appendix 3.
(A) -30 (B) -20 (C) -10 (D) 0 (E) 10 (F) 20 (G) 30
A
(13) What is the ΔH (in kcal/mol) for the monochlorination of cycloctane with Cl2 when tiny
elves wield small paring knives and chop up the molecules into atoms and then put them
back to create chlorocyclooctane and HCl? See Appendix 3.
(A) -30 (B) -20 (C) -10 (D) 0 (E) 10 (F) 20 (G) 30
(14) Which of the following statements is the best statement of the Hammond Postulate?
(A) In an endothermic reaction, the transition state is closer to the reactants in structure.
(B) In an exothermic reaction, the transition state is closer in energy to the products.
(C) Related species that are similar in energy are also similar in structure.
(D) The structure of the transition state in an organic reaction is always modeled on the
structure of the reactants leading to that transition state.
(E) Transition states are molecular species of finite lifetime whose properties can be probed
through free radical reactions.
A
(15) How many different carbons in 1,3-cyclohexadiene can be halogenated via allylic
monobromination?
(A) 1 (B) 2 (C) 3 (D) 4 (E) 5 (F) 6 (G) 0
F
(16) Which of the following is not a possible termination step in the free radical
chlorination of methane?
(A) ·CH3 + Cl2 --> CH3Cl + Cl·
(A) generates a radical and thus, is not a termination step.
(B) ·CH3 + Cl· --> CH3Cl
(C) ·CH3 + ·CH3 --> CH3CH3
(D) ·CH3 + wall --> CH3-wall
(E) Cl· + wall --> Cl-wall
(17) When 1,1,3,3-tetramethylcyclobutane is brominated at 125°C, the relative reactivity
of the 1°: 2°: 3° hydrogens is approximately 1:82:1600. Estimate the amount of the
primary monobromide product among all the monobromination products.
(A) 1.2%
(B) 2.4%
(C) 3.5%
(D) 7.0%
(E) 82%
(F) 100%
12 primary H; 4 secondary H. % primary = 12x1/(12x1 + 4x82) = 3.5%
(18) When H· reacts with 1-butene, which hydrogen atom is preferentially abstracted?
(A) CH3CH2CHCH2 (B) CH3CH2CHCH2 (C) CH3CH2CHCH2 (D) CH3CH2CHCH2
A
(19) Which of the following is not a radical?
(A)
(B)
(C)
Cl
H O
H
C
H
(D)
H C
H
(E)
H B
A
C
C
B
H
H
(20) How many distinct dichlorination products can result when isobutane is subjected to
Cl
Cl Cl
Cl
free radical chlorination?
Cl
(A) 1
(B) 2
(C) 3
(D) 4
(E) 5
(F) 6
Cl
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C