CHM 211 (01) - Turnbull
FINAL EXAM
Fri., November 18, 2005
Answer Key
Answer all 34 questions [6 pages] (150 pts).
*1. (8) By assigning priorities to the groups attached, designate either E or Z or R or S (as
appropriate) to each of the following molecules. You must show all the priorities (#1 = highest) to
receive full credit.
a)
4
O
1
b)
Br
3
4
OH
N
2
(S)
(E)
1 F
3
Br
2 CN
*2. (8) Name the following molecules using IUPAC rules. Do not assign E or Z designations.
a)
b)
1-ethyl-2-isopropyl-4-(2-methylpropyl)cyclohexane
7-ethyl-5-methyl-1-nonen-8-yne
*3. (2.5) Which of the following isolated elements has 5 valence electrons?
a) Oxygen, atomic number 8 b) Nitrogen, atomic number 7
c) Carbon, atomic number 6 d) Boron, atomic number 5
*4. (2.5) Which of the following compounds is ionic?
a) HI
b ) KC l
c) N I3
d) ICl
a)
*5. (3) Which of the following species (as written) possesses a net neutral charge?
*6. (2.5) How many tertiary carbon atoms are present in the molecule shown?
a) two
b) three
c) four
d) fiv e
(C H 3 )2 CH CH 2 CH(CH 3 )CH2 CH(CH 3 )2
H C H
H
*7. (3) Which C6H14 isomer shown below can afford only two mono-chloro derivatives upon
reaction with Cl2 and light?
a)
b)
c)
d)
CH 3C H 2CH 2 CH 2CH 2 CH 3
(CH 3) 2 CH CH 2C H2 CH 3
( CH 3)2 CHCH (CH 3)2
(CH 3) 3 CC H 2 CH 3
C
*8. (2.5) True or False? The rate of reaction for an SN2 reaction is faster in polar, protic
solvents.
*9. (2.5) Draw the conjugate base of HOCH3.
CH3O_
*10. (2.5) True or False? For nucleophilic ability, the general trend is: "the weaker base,
the better the nucleophile."
*11. (9) For each of the following pairs, circle all of the statements to their right which are correct.
a)
COOH
H
COOH
OH
HO
H
H
HO
H
and
OH
OH
HO
COOH
•
•
•
•
•
•
H
H
COOH
b)
Cl
H
mirror images
enantiomers
identical
meso
stereoisomers
diastereomers
NH2
CH2CH 3
H
and
Cl
CH2CH 3
NH2
•
•
•
•
•
•
mirror images
enantiomers
identical
meso
stereoisomers
diastereomers
*12. (2.5) True or False? The mirror image of a meso compound is a stereoisomer of the
original compound.
*13. (2.5) What is the general formula for a cycloalkene?
a) CnHn
b) CnH2n
c) CnH2n+2
d) CnH2n-2
*14. (2.5) What compound is represented by the Newman projection shown?
a)
b)
c)
d)
CH 3CH 2CH3
(CH 3) 2CHCH 2CH 3
H3CCH(CH 3)2
(CH 3) 2CH2
CH3
H
H
H 3C
H
H
*15. (2) Which of the following alkenes liberates the most heat when hydrogenated with
H2, Pd ?
b)
a)
d)
c)
*16. (2.5) Which of the following carbocations is the most stable?
a)
CH3
b) CH3 -CH 2
c) CH3-CH-CH 3
d)
CH3
H3 C C CH2
CH3
*17. (2.5) Which of the following is the strongest acid?
a)
NH3
b) CH4
c) H C C H
d) H2O
*18. (2.5) Which has the stronger conjugate base, water (H2O, pKa = 15) or ammonia
(NH3, pKa = 36)? NH3
*19. (2.5) Which has the weaker conjugate base, water (H2O, pKa = 15) or methane
(CH4, pKa = 40)? H2O
*20. (2.5) Which of the following describes the most stable conformer of trans-1-tertbutyl-2-methylcyclohexane?
a) The tert-butyl group is equatorial and the methyl group is axial
b) The tert-butyl group is axial and the methyl group is equatorial
c) Both groups are equatorial
d) Both groups are axial
*21. (2.5) The addition of HI to 3-methyl-1-butene, (CH3)2CHCH=CH2, gives which of
the following products?
a)
CH3
IH 2C C C CH3
H H2
b)
CH3
H 3C C C CH3
H2
I
c)
CH3
H
H 3C C C CH3
H
I
d)
CH3
H 3C C C CH2 I
H H2
*22. (2.5) The oxymercuration (1. Hg(OAc)2, H2O; 2. NaBH4) of 3-methyl-1-butene,
(CH3)2CHCH=CH2, gives which of the following products?
a)
HOH 2C C C CH3
H H2
CH3
CH3
CH3
b)
H 3C C C CH3
H
OH 2
c)
H
H 3C C C CH3
H
OH
d)
CH3
H 3C C C CH2 OH
H H2
*23. (2.5) The hydroboration (1. BH3; 2. H2O2, HO-) of 2-methyl-2-butene,
(CH3)2C=CH-CH3, gives which of the following products?
a)
CH3
HOH 2C C C CH3
H H2
b)
CH3
H 3C C C CH3
H
OH 2
c)
CH3
H
H 3C C C CH3
H
OH
d)
CH3
H 3C C C CH2 OH
H H2
*24. (2.5) An unknown alkene having the formula C6H12 yields (CH3)2CHCH2CHO and
H2CO upon ozonolysis with O3 then Zn / H3O+. What is the structure of this alkene?
a)
b)
c)
d)
*25. (7.5) State, in each case, whether (or not) the following pairs are resonance forms of one
another.
a)
S
S
an d
b)
O
O
c)
NH2
O
resonance
an d
O
O
not resonance
an d
H
O
NH
not resonance
*26. (2.5) In the following, based on the information provided, state whether or not the reaction
shown would occur.
H
+
H
H
pKa = 45
H
CH3 OK
H
K
+ CH3 OH
pKa = 16
reaction
would not
occur
*27. (3) For the following, circle all of the statements to the right which are correct.
*28. (3.5) The degree of unsaturation (rings and/or multiple bonds) for the formula C5H5BrClNO is:
a) 3
b) 4
c) 5
d) 6
*29. (2.5) In the molecule below, assign the hybridization of the nitrogen atom.
N
sp2
*30. (15) True or False? (Circle your choice).
a) Primary carbocations are more stable than tertiary carbocations
b) In an SN2 reaction of (S)-2-bromobutane, the product must have
the (R) configuration
c) CH3— is a better nucleophile than HO—
d) CH3— is a better leaving group than HO—
e) In an SN2 reaction of (S)-2-bromobutane, doubling both its concentration
and that of the nucleophile would quadruple the rate of reaction
f) The SN2 reaction generally proceeds fastest where there is the least
steric hindrance to the attack of the nucleophile
T or F
T or F
T or F
T or F
T or F
T or F
*31. (31) In each of the following reactions, reactants or products are missing. Fill in the blanks
with the appropriate molecules. If more than one step is involved, indicate this by using 1)......;
2)........ If more than one product could be formed, show only the major product(s). Where
appropriate, draw the stereochemistry of the product(s).
a)
1) NaNH2
2) CH3CH2Br
b)
HgSO4
H3O+
c)
1) BH 3
2) H2O2, HOd)
KMnO4 / H3 O+
O
H
OH
H
O
OH
O
e)
Br
Br2
Br
f)
H
1) Li / NH 3
2) H2O
g)
H
excess HBr
OH
Br
Br
Br
*32. (3) From the molecule shown, draw a Newman projection by viewing the molecule along the
central C-C bond as designated below.
A
H3C
H
Cl
H
OH
Br
H
Cl
CH3
HO
Br
H
*33. (3) The conformation shown below is?
H
H
CH3
a)
b)
c)
d)
Staggered and the most s table conformer
Staggered and the leas t stable conformer
Eclipsed and the mos t stable conformer
Eclipsed and the least stable conformer
CH3
*34. (3) The best nucleophile among the choices below would be a substance with?
a)
b)
c)
d)
A positive charge on an electronegative atom
A negative charge on an electronegative atom
A positive charge on a non-electronegative atom
A negative charge on a non-electronegative atom