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rI'IHITIIBIH UI'IIVERSITY
0F SCIEITCE HUD TECHNOLOGY
FACULTY OF HEALTH AND APPLIED SCIENCES
DEPARTMENT OF NATURAL AND APPLIED SCIENCES
QUALIFICATION: BACHELOR OF SCIENCE
QUALIFICATION CODE: 07BOSC LEVEL: 6
COURSE CODE: ORC601S COURSE NAME: ORGANIC CHEMISTRY 1
SESSION: JULY 2017 PAPER: THEORY
DURATION: 3 HOURS MARKS: 100
SECOND OPPORTUNITY/SUPPLEMENTARY EXAMINATION QUESTION PAPER
EXAMINER(S) DR. MARIUS MUTORWA
MODERATOR: PROF. HABAU KA KWAAMBWA
INSTRUCTIONS
Answer ALL the questions.
Write clearly and neatly.
Number the answers clearlyPINE"? All written work must be done in blue or black ink and sketches can
be done in pencil
5. No books, notes and other additional aids are allowed
PERMISSIBLE MATERIALS
Non-programmable Calculators
ATTACHMENTS
pKa Chart and Periodic Table
THIS QUESTION PAPER CONSISTS 0F 13 PAGES
(Including this front page, pKa Chart and Periodic Table)
SECTION A [60]
QUESTION 1: Multiple Choice Questions [60]
0 There are 30 multiple choice questions in this section. Each question carries
2 marks.
0 Answer ALL questions by selecting the letter of the correct answer.
0 Choose the best possible answer for each question, even if you think there is
another possible answer that is not given.
1.1 Rank the acidity of the labelled protons in the following molecule from the lowest to the highest
acidity.
Hb
Ha/OMCchO
A. Ha; Hb; Hc
B. Hb; HC; Ha
C. Hc; Ha; Hb
D. Hb; Ha; Hc
1.2 List the following compounds in the order of increasing acidity.
O O
A_ /\ B, )LOH c. CH30H D. FQLOH
A. A; B; C; D
B. A; C; B; D
C. A; C; D; B
D. D; C; A; B
1.3 Which of the following is a true statement?
All chiral molecules possess a plane of symmetry
All achiral molecules are meso
All molecules which possess a single chirality center of the 5 configuration are levorotatory.
A mixture of achiral compounds will be optically inactive.F1909“? All molecules which possess two or more chirality centers will be chiral.
Page 2 of 13
1.4 Which of the following species is the strongest base?
A. NHz’
B. CH
C. 0'
D. l'
1.5 Does the equilibrium of this reaction lie to the left or right?
0 O
(E) _
o + CH3OH _ OH + CH30‘—
A. Left
B. Right
C. It cannot be determined
D. The forward and reverse reactions are equally favoured.
1.6 The pKa of CH3COOH is 4.8 and the pKa of HCOOH is 3.8. Given this information, one knows
that
CH3COOH completely ionizes in water
HCOOH is a weaker acid than CH3COOH
HCOO- is a weaker base than CH3COO-
CH3COOH reacts with HO- while HCOOH does not
HCOOH reacts with HO' while CH3COOH does not”POP”?1.7 H-A is an acid with a pKa of 4.5. Which of the following statements about an aqueous solution
of H-A is true?
At pH = 4.5, the solution contains much more H-A than A-
At pH = 4.5, the solution contains much more A' than H-A
At pH- 3.5, the solution contains about 90% A- and 10% H-A
At pH = 6.5, the solution contains about 80% A' and 20% H'A
At pH = 5.5, the solution contains about 90% A' and 10% H-AF1
U
s1
P3
P
1.8 Identify the following compounds as R or 5.
Br H O CH2CH5
l //F——c——Cm
cm——f——m——c——F
Cl 0H 0H éHBPage 3 of 13
in.“ :05"
monw> 1"?” Mm ”MC/1U)”3° 2°
1.9 How many stereogenic centres does the addictive drug heroin have?
.005»? \lO‘U‘l-fi
CH3000
CHgooo‘“heroin
addicting drug
1.10 In question 1.9 above, how many stereoisomers are possible for the drug heroin?
A
B 16
C. 32
D. 64
1.11 Which compound would you predict to be highest in energy?
Cl
A.A
B.B
C.C
DB
——>
step 1
Cl
step 3
OH
A+ HCI
Page 4 of 13
1.12 In question 1.11 above, what kind of reaction does the conversion of A to D represent?
A. Addition
B. Elimination
C. Subtraction
D. Substitution
1.13 Consider the three isomeric alkanes n-hexane, 2, 3-dimethylbutane, and Z-methylpentane.
Which of the following correctly lists these compounds in order of increasing boiling point?
2, 3-dimethylbutane < 2-methylpentane < n-hexane
Z-methylpentane < n-hexane < 2, 3-dimethylbutane
2-methylpentane < 2, 3-dimethylbutane < n-hexane
n-hexane < 2-methylpentane < 2, 3-dimethylbutaneP199095? n—hexane < 2, 3-dimethylbutane < 2-methylpentane
1.14 Among the butane conformers, which occur at energy minima on a graph of potential energy
versus dihedral angle?
gauche only
eclipsed and totally eclipsed
gauche and anti
eclipsed only.mposw? anti only
1.15 Which of the following compounds is most likely to show first-order kinetics in a substitution
reaction?
Br
OA/Br
0kBr
mBr
0XA B C D
A.A
B.B
CC
0.0
1.16 Given the following substitution reaction, what would the effect be of changing the solvent
from ethanol to DMSO?
CH3(CH2)5BF + NaOH ——>CH3(CH2)5OH + Bl’
Page 5 of 13
A. The rate would increase because 5N2 reactions favour a polar aprotic solvent
B. The rate would decrease because 5N1 reactions favour a polar protic solvent
C. The rate would not be affected by the change in solvent.
D. The potential change cannot be predicted
1.17 Which of the following anions is the best leaving group?
A) NHz— B) Cl" C) CH3" D) OH
A.A
B.B
C.C
D.D
1.18 Which of the following compounds will react most rapidly with HCl?
W909”?S-methyl-l-hexene
4—methyl-1-hexene
(E)~5—methyl-2-hexene
(E)-2—methy|-3-hexene
2-methyl—2—hexene
1.19 For an endergonic reaction step, the Hammond postulate allows one to say that
W909”?the transition state of the step resembles the reactants of the step
the transition state of the step resembles the products of the step
the step is rate-determining since it has the smallest Ea
the reaction containing this step is overall first order
the transition state is precisely symmetric with bond-breaking and bond-forming occurringto the same extent
1.20 Which of the following is the strongest nucleophile in polar protic solvents?
A) IT B) CH3O‘ C) HO— D) CHgs'
A.A
B.B
C.C
D.D
Page 6 of 13
1.21 What is the major product from the acid-catalyzed hydration of 2—methyI—2-pentene?
2-methylpentane
2-methyl-1-pentanol
2-methyl-2-pentanol
2-methyl-3—pentanolF1909”? 1-methoxypentane
1.22 Give the product for the reaction of l-butene with methanol in the presence of acid.
1-ethoxybutane
2-ethoxybutane
1—methoxybutane
2-methoxybutane1119095? 1—butanol
1.23 Which of the following carbocations is the most stable?
++
+ +
A B C D
A.A
B.B
C.C
D.D
1.24 Which alkyl halide (A-C) would give the alkene Y as the only product in an elimination
reaction?
Cl
A B C Y
A. A
B. B
C. C
D. Aand B
Page 7 of 13
1.25 What is the IUPAC name for the following compound?
H H
\ /c=c H
CH3 c=c
H CH2CH3
cis, trans-2, 4—heptadiene
22,4Z—2, 4—heptadiene
cis, cis-2, 4—heptadiene
trans, trans-2, 4—heptadiene
2E,4E-2, 4—heptadieneW909”?1.26 Which of the following statements is (are) true about an E2 elimination reaction?
A. It is fastest with 3° Halides
B. It exhibits second-order kinetics
C. A better leaving group should make a faster reaction
D. All of the above are true
1.27 Assuming no other changes, what is the effect of doubling both the alkyl halide and the
nucleophile concentrations in a 5N2 reaction?
A. no change
doubles the rate
triples the rate
quadruples the rate
rate is halvedwoos”1.28 Give the IUPAC name for the following compound.
Br
Cl
A. (Z)-1-bromo-2—chloro-2—ethyl-4—methyl-1—pentene
B. (E)-1—bromo-1—ch|oro-2—ethy|—4—methy|—2-pentene
C. (Z)—1-bromo-1—chloro-Z-ethyl—4-methyl-l-pentene
D. (E)-1-bromo-1-chloro-2-ethyI-4—methyl-1—pentene
Page 8 of 13
1.29 Which of the following reaction conditions would result in the anti-Markovnikov addition to
the alkene?
A) H20/H+ B) HBr C) HC] D) [1]BH3; [2] H202/0H_
1.30 Give the IUPAC name of the following compound.
CH3C(CH3)2CH2CECCHgCH(CHgCH2CI-I3)CH3
A. 2,2,7-trimethyI—4-nonyne
B. 2,2,7-trimethyI—4-decyne
C. 3,3,7-trimethyl-4-decyne
D. 2,2,6-trimethyl-4-undecyne
Page 9 of 13
SECTION B: [0]
QUESTION 2 [10]
What is (are) the product(s) of the following reactions? Represent the products as skeletal
structures and show the stereochemistry where necessary.
Note: Each question carries 2 marks.
'
Substitution onlya) "Br + CHSOH ——-————>
b) Br +
X—>—
Br _
NH2—____’_
c)-
Br(2 equwalents)
1) 8H3——>
d) W2, HZOZIOH'
H2
__ ————>
Lindlar's catalyst
Page 10 of 13
QUESTION 3 [10]
Determine the reagents required to achieve each of the following transformations.
Note: Each question carries 2 marks.
a) )\/OH —————> /l\/Cl
?Br
b)______>
B
?
a) Q - Q—-——-> Br OH r‘ 0H
? Q
d) ——_—
—-——>\Jk
/7
e) M _—__> A/
QUESTION 4 [10]
Draw a stepwise, detailed mechanism for the following reaction. In order to receive full
marks, show all the electron movement, the intermediates and all the products formed.
‘I
water
__... ?
QUESTION 5 [1 0]
Draw a stepwise, detailed mechanism for the following reaction. In order to receive full
marks, show all the electron movement; draw all the intermediates and all the products.
Hint: The reaction produces two alkene products
CH3“CI ‘OH
———>
THE END
GOODLUCK
Page 11 of 13
pKaChart
con'uoatebase
con'u
ate
base
sulfuricacid
H2804
,
HSO4_
_10
hydrogencyanide
H—CENi—pTCEN:
9-1
(cyanide)
hydroiodicacid
H!
—iI-v
[‘
-9
-
-
.
-,—
9H
.0.-
_
.
_
phenols
—>-
10
hydrobronncac1d
HBr
—>-
Br
-8
hych‘ochloficacid
H01:
"
:91:
—7
water
J'OiH
—>-
—:b'—H
15.7
(hydroxide)
cai‘bocationsM
__,_
/
_3
primaryalcohols
/\
x
H
—D-
A5:—
16
.
‘
Dioxides)
piotonated
_
V
H
H
(1
alcohol
/\O+
/\6’
_2'4
I
"
alkynes
CEO—H
—I~
CEO?
26
(acetylideanions)
H
.
.
Ej
+
.
.
hydroniunl1011
H
’l
N
-
H
H
—>
H,.0,~.H
—1-7
hydrogen
H—H
*—
=H_
amide)
35
.q
mlnlonian’amines
R’.
.\
H
—I-
R/D's-
H
36
'hych‘ofluoricacid
HF
——>
F“
(amidebases)
:0:
:0:
alkanes
fl
4—
A1—
~60
carboxylicacids
/IJ\.O.,H
—"
/”\..—
4.8
H
O.
.0
II
nitricacid
HNO3
——D-No;
—1.3"3m
hydrcgen
1 H1
.0679 ltthlum
belylllJm
Li
Be
6.941
9.3122
sadiJm
magwslum11 Na
Mg
22.990
21-3305
helurr 2 He 4.0026
D0101 5 B 10811
canon G C 12.31‘
nltrogen 7 N 14.007
oxygen 8 O1
5.999
tluorlne 9 F 18998
“16311 Ne 20.180
aluminlurr 13 AI 26.9E2
silicor Si 28.386
phcsphorus 15 P 30.974
sulfur 16 S 32.065
chlarine 1
7
CI 35453
argon 18 Ar 39.948
paiassium
cdclum
KCa 39.1398
40.078
scondlurn 21 Sc 44.956
titan'um 22 Ti 47.867
vanadiJm 23 V 50.942
[71519671659 25 Mn 54.936
‘33 Fe 55.845
cobalt 27 Co 58.933
nlcke 28 Ni 58.693
zin:
gdliu‘n 31 Ga 69.723
gamanium 32 Ge 72.51
arsenlc 33 As 74.922
selen'um 34 Se 78.56
brcmine 35 Br 79.904
krypton 36 Kr 83
80
rubidium
Stmnlum
37 Rb
Sr
85.468
87.62
{MI'UIT 39 Y 88.906
zir:onium 40 Zr 91.224
nioble Nb 92.906
technatlum 43 Tc [93]
rut'tenium
l'hOdiLm 45 Rh 1132.51
pallzdiLm 46 Pd 106.42
indium 49 In 114.E2
2% Sn 118.7’
artln‘ony 51 Sb 12176
telutLIm 52 Te 127.60
lodlne 53 126%
xenon 54 Xe 131.29
caesurn
bariLm
55
565
Cs
Ba
132.91
137.33
lutezlun 71 Lu 174.97
hafnlun' 72 Hf 178.49
tantalum 73 Ta 160.95
rherlun 75 Re '86.21
lridium
77 Ir 192.22
platnu-n 78 Pt 195.08
200.59
thallium 81 TI 204.58
Pb 207.2
b
SfTuli‘ Bi 20898
pobnlurr 84 P0 [209]
astatlne 85 At [210'
[2120n
86 Rn [222]
trandunl
78:111.!“ 88
Fr
Ra
[223]
[226]
18WrenCium
103 Lr [262]
1111118170111[J
m
104 Rf '261]
dubniurn 105 Db [262]
bohrlun 1
07 Bh [2641
melhelium 109 Mt [2681
ununnlllum 110 Uun [271]
ununtzium 112 lUub
*Lanthanideseries
*
*Actinideseries
Jnanuadum 114 Uuq ._L_91_
lanthanum 57 La 1389‘
cerium 58 Ce 14012
pmseadymiurn 59 Pr 140.91
promethIJm 61 Pm [145]
sama'lum 62 Sm 150.36
eurolem 63 Eu 151.96
gadollnlJm Gd 157.25
dysamslurn Dy 152.50
holmlum 67 Ho 164.93
artlum 68 Er 167.26
thullun' 69 Tm 168.93
ytterblurn
70 Yb 173.34
:ctinium 89 Ac 12271
lhor'um 90 Th 23204
plotacthium 91 Pa 231.04
nepthiLm NP [2371
plLlonium 94 Pu 241]
americium 95 Am [2431
cutiun 96 Cm [2471
californium 98 Cf 125H
enszeiriun 99 Es [252]
fermium 100 Fm [2
57]
merdeevurr
101 M [258]
nonelum
102 No [2591
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