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ORC601S - ORGANIC CHEMISTRY 1 - 2ND OPP - JULY 2023 |
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nAmlBIA unlVERSITY
OF SCIEnCE AnD TECHnOLOGY
FACULTYOF HEALTH,NATURALRESOURCESAND APPLIEDSCIENCES
SCHOOLOF NATURALAND APPLIEDSCIENCES
DEPARTMENT OF BIOLOGY,CHEMISTRYAND PHYSICS
QUALIFICATION: BACHELOROF SCIENCE
QUALIFICATION CODE: 07BOSC
LEVEL: 6
COURSECODE: ORC601S
SESSION:JULY 2023
COURSENAME: ORGANIC CHEMISTRY 1
PAPER:THEORY
DURATION: 3 HOURS
MARKS: 100
SUPPLEMENTARY/SECONDOPPORTUNITYEXAMINATION QUESTION PAPER
EXAMINER{S) DR. MPINGANA AKAWA
MODERATOR: PROF. HABAUKA KWAAMBWA
INSTRUCTIONS
1. Answer ALL the questions.
2. Write clearly and neatly.
3. Number the answers clearly.
PERMISSIBLEMATERIALS
Non-programmable Calculators
ATTACHMENTS
pKa Chart and Periodic Table
THIS QUESTION PAPERCONSISTSOF 10 PAGES(including this frontpage)
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SECTION A
(50]
QUESTION 1: Multiple Choice Questions
• There are 25 multiple choice questions in this section. Each question carries 2 marks.
• Answer ALL questions by selecting the letter of the correct answer.
1.1 Consider the following acid-base reaction. The equilibrium for this reaction lies to the:
A. Left
B. Right
C. It cannot be determined
D. The forward and reverse reactions are equally favoured
1.2 What is the hybridization of Carbon atom in CF4?
A. sp2
B. sp3d
C. sp3
D. sp
1.3 Which of the following is not a nucleophile?
A. ·cN
B. CH3NH2
C. CH30·
D. H20
E. +N02
1.4 Consider the three isomeric alkanes n-hexane, 2, 3-dimethylbutane, and 2-methylpentane. Which
of the following correctly lists these compounds in order of increasing boiling point?
A. 2, 3-dimethylbutane < 2-methylpentane < n-hexane
B. 2-methylpentane < n-hexane < 2, 3-dimethylbutane
C. 2-methylpentane < 2, 3-dimethylbutane < n-hexane
D. n-hexane < 2-methylpentane < 2, 3-dimethylbutane
1.5 Among the butane conformers, which occur{s) at energy minima on a graph of potential energy
versus dihedral angle?
A. gauche only
B. eclipsed and totally eclipsed
C. gauche and anti
D. eclipsed only
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1.6 The name 2,4,6-tribromobenzene
A. tribromobenzene
B. 2,6-dibromobromobenzene
C. 3,5-dibromobromobenzene
D. 1,3,5-tribromobenzene
is incorrect. Which of the following is the correct name?
1.7 What is the IUPAC name of the following compound?
CH3C CCH1C(CH,1,
A. 4,4-dimethyl-2-hexyne
B. 5,5-dimethyl-2-hexyne
C. 5,5-dimethyl-3-hexyne
D. None of the above
1.8 Which of the following reaction conditions would result in the anti-Markovnikov
addition to the alkene?
A. H20/W
B. HBr
C. HCI
D. BH3: [2] H20i/OH-
1.9 Markovnikov addition of HBr to 1-propene involves:
A. Initial attack of bromide ion
B. Initial attack of bromine radical
C. Formation of a secondary carbocation
D. Formation of a primary carbocation
1.10 Which is the order carbocations stability?
A. tertiary> secondary> primary
B. secondary> tertiary> primary
C. primary> secondary> tertiary
D. primary> tertiary> secondary
1.11 Bromination of alkanes is a much slower reaction than chlorination. Which of the following is
expected to be the major organic product when 2-methylbutane is allowed to react with Br2 in the
presence of light or heat?
yH3
CH3CH2CHCH3 + Br2
yH3
CH3CH2CHCH2Br
A.
yH3
CH3CHzyCH3
Br
B.
yH3
CH3yHCHCH3
Br
C.
yH3
BrCH2CH2CHCH3
D.
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1.12 Which of the following is a product of the acid-catalyzed hydration of 3-methyl-2-
pentene?
A. 2-methylpentane
B. 3-methyl-1-pentanol
C. 3-methyl-3-pentanol
D. 2-methyl-2,3-pentadiol
1.13 What is the molecular geometry of the central atom in CH30(H3?
A. Trigonal planar
B. Trigonal pyramidal
C. Tetrahedral
D. Bent
1.14 Carbon-carbon double bonds consist of:
A. one a bond, one TI bond
B. two a bonds, one TI bond
C. one a bond, two TI bonds
D. two a bonds, two TI bonds
1.15 Which of the following anions is the best leaving group?
A. NH2-
B. c1-
C. CH3-
D. OW
1.16 Which of the following reaction conditions would result in the anti-Markovnikov
alkene?
A. H20/W
B. HBr
C. HCI
D. [1] BH3[2] H202/0W
addition to the
1.17 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 loro-2-ethyl-4-methyl-2-pentene
C. (Z)-1-bromo-1-chloro-2-ethyl-4-methyl-1-pentene
D. (E)-1-bromo-1-chloro-2-ethyl-4-methyl-1-pentene
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1.18 What is the nucleophilic site in each of the following molecules?
8.
A. A: hydrogen; B: nitrogen; C: 2 electrons in bond
B. A: oxygen: B: nitrogen: C: carbon
C. A: oxygen; B: nitrogen; C: 2 electrons in bond
D. A: oxygen: B: carbon; C: 7 electrons in bond
1.19 Which molecule has a nonzero dipole moment?
A. Cli
B. CO2
C. CCl4
D. CHCl3
1.20 Which of the following properties are not identical for constitutional isomers?
I. Molecular formula II. Molecular Weight Ill. Order of attachment of atoms. IV. Physical
Properties
A. I; IV
B. II; Ill
C. I; II
D. 111I;V
1.21 Using Markovnikov's rule, predict the position of the Cl atom in the major product from
the reaction of 1-methylcyclohexene with HCI.
A. A
B. B
C. C
D. D
1.22 Which of the following reagents must be used with HBr to convert 1-hexene to 1-
bromohexane?
A. Hso3•
B. NaBH4
C. ROOR
D. Pd/C
E. no other reagent is necessary.
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1.23 The reactivity of alkyl halides in E2 elimination reactions follows the order ___ _
A. R-1 < R-Br < R-CI < R-F
B. R-F < R-CI < R-Br < R-1
C. R-1 > R-CI > R-Br < R-F
D. R-1 < R-Br < R-F < R-CI
1.24 Give the IUPAC name of the following compound.
CH3C(CH3J2CH2c=ccH2CH(CH2CH2CH3)CH3
A. 2,2, 7-trimethyl-4-nonyne
B. 2,2,7-tri methyl-4-decyne
C. 3,3,7-trimethyl-4-decyne
D. 2,2,6-trimethyl-4-undecyne
25. What is the correct name of the following compound
OH
A. 3-methylbenzoic acid
B. m-methylbenzoate
C. tolylcarboxylate
D. methylbenzoate
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SECTION B
• There are SIX questions in this section. Answer all Questions.
QUESTION 2
[SO]
(31
2.1 Explain the following observations
a) The boiling points of unbranched alkanes increases with increase in molecular weight.
b) Alkanes are insoluble in water
c) The melting points of isomeric alkanes increases on branching.
QUESTION 3
(10]
3.1 Draw the structural formulas or bond line (zigzag) formula of the following compounds:
a) 3,3-dichloro-2-methylhexane
b) 3,4-dimethyl-2-pentanol
c) 2,3,3-Trimethyl-1,4,6-octatriene
d) 5,5-dimethyl-2-hexyne
e) 2,5-dimethyl-3,6-octadiene
QUESTION 4.
(10]
4.1 Give systematic IUPAC names of the following organic compounds.
(a)
(b)
(c)
LJ
(d)
(e)
(X Br
0
I
II
CH3CHCH2CH2COH
QUESTION 5
(81
5.1 Write and identify the functional groups in the following molecules.
(a)
(b)
(c)
~Cl
0
QUESTION 6
[7]
6.1 Draw a full detailed mechanism of the reaction of 2-methylpropene with hydrochloric acid. Give
the IUPAC name of the product. In order to receive full marks, show the flow of electrons using
arrows and all the intermediates, which are formed during the reaction.
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QUESTION 7
[12]
7.1 Predict the product{s) of the following reaction
1. Hg(OAc)2, H20
(a)
2.NaBH 4
CH3
I
CH3CH2, -1/C,
1. BH3
(b)
C
CH3 2. NaOH, H202
I
H
H
Uc"'c,.,H I
(c)
Cl2, H20
u (d)
~O. ~S_0 4
H
Ucl"'c,.,HBr2
(e)
UOCH3 HCI
(f)
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coniugate acid
t?
..
sulfuric acid
H2SO~
hydroiodic acid
HI
hych-obromicacid HBr
hydrochloric acid
HC..I:
H
/0 crubocationc..
+
protonorecl /""--o,, H
alcohol
14-
H
hydronitun ion H.,.0./ ·'+H
H
uitric acid
HN0 3
hydro.tluoric ncid HF
:o:
)lo,.,.. carboxylic acid~
H
conjug;1te base
Hso;
,-
-
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:c..·1.-:
..
.. /""-- .. ,,..H
0
H,,.0·•'H
NOa
F-
:o:
)lo.:.
pKa Chart
conjugate acid
conju~atc base
-10
-9
hydrogen cyanide H-c=N:
:c=N:
9.1
phenols
u~Ha~=- ..
(cyanide)
10
--8
--7
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--2.4
--1.7
-1.3
3.2
4.8
water
H,,•."c'Hi•
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alk.--y:ue~
c=c-H
hvdroo::e:, u
muuonia/ amines
H-H
H
I
R,,.N. •'H
alkaucs
H
-:0-H
15.7
(h,yd,r,ox,id,0.e-.) :--..1.6
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c=c:
26
(acecylideanions)
:H (hydride) 35
N._
R,,.•. •,H
36
(amide bases)
. /'-... -
~60
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