ORGANIC CHEMISTRY

Question 1

Friedrich Wohlers work on isomerism
was able to curb the growth of vitalism
by disproving the old notion that organic
compounds can only come from organic
sources. Which among the following was
the product produced in Wohler’s
synthesis?
A: Ammonium Cyanate B: Urea
C: Carbon Disulfide D: Acetic Acid

Answer 1

B: Urea

Question 2

What are sigmatropic rearrangements in organic
reactions?
A. They are similar to the ‘(3, 3) Cope
rearrangement where the beta ring of a steroid
undergoes photos activated retro
electrocyclization.
B. They are thermal reactions which do not allow
the formation of six-membered benzene ring with
a cis-or trans-alkene, such as in the formation of
vitamin D3.
C. They are different from electrolytic reactions
wherein movement of a sigma bond with a
simultaneous rearrangement of the pi-system
does not occur.
D. They are not the same to the (3, 3) cope
arrangement and the beta ring does not undergo
photon activated retro electrocyclization.

Answer 2

C. They are different from electrolytic reactions
wherein movement of a sigma bond with a
simultaneous rearrangement of the pi-system
does not occur.

Question 3

What type of polymer is used for bulletproof
vests?
A. Linear polyethylene fiber
B. Polyacrylonitrate fiber
C. Polycarbonate fiber
D. Polymethacryclate fiber

Answer 3

A. Linear polyethylene fiber

Question 4

What compound can be used to convert alcohol
or a phenol into an ester?
A. Acetic anhydride: CH3-C-O-COCH3
B. Benzamide
C. Maleic anhydrate: CH3-CH2-COO-CH3
D. Aqueous bromine solution

Answer 4

A. Acetic anhydride: CH3-C-O-COCH3

Question 5

Adrenaline is produced in the body through a
biochemical nucleophilic substitution reaction
where:
A. The leaving groups are larger and more complex
than the halogen atoms frequently in nucleophilic
substitution reactions.
B. According to Markovnikov’s rule, the
biosynthesis of epinephrine adds hydrogen atoms
to the double banded carbon atom.
C. The nucleophilic nitrogen atom of
norepinendrine from a covalent bond with the CH3
of S adenosylmethionine
D. The reactant neocleophile atom replaces the
leaving group in the nucleophylic substitution
reaction.

Answer 5

D. The reactant neocleophile atom replaces the
leaving group in the nucleophylic substitution
reaction.

Question 6

Fatty acid such as lauric acid and palmitic acid
and oleic acid are long unbranched carboxylic
acids consisting of 12 to 20 carbon atoms. Which
type of fatty acid should people avoid ingesting,
saturated or unsaturated and why?
A. Saturated, because the risk of cardiovascular
disease is increased.
B. Fatty acids are safe to ingest.
C. Unsaturated, because the risk of cardiovascular
disease is increased.
D. Both fatty acids, because the risk of
cardiovascular disease is increased.

Answer 6

A. Saturated, because the risk of cardiovascular
disease is increased.

Question 7

The person’s senses of smell and taste depend
on specific biochemic receptors present in a
person’s nose and mouth. In 2004, a Nobel prize
was given to the researchers who established this
fact and identified the type of organic compound
associated with the sense of smell and taste.
The chemical identified was;
A. an alcohol
B. rhodopsin
C. an ester
D. an isomer

Answer 7

B. rhodopsin

Question 8

These compounds are formed by the reaction of
acids with alcohols.
C. Bases
A. Ethers
B. Esters
D. Enzymes

Answer 8

B. Esters

Question 9

In a dehydration reaction where water is lost,
an organic compound C3H80
reacts with concentrated phosphoric and a product
is formed. This
product rapidly decolorizes a solution of bromine
in tetrachlormethane.
What is a product?
A. Propanol
B. Propanolol-2
C. Propene
D. Propanol-1

Answer 9

C. Propene

Question 10

What organic product is formed when
C6H5CH2COOH is treated with CH3OH +
H2 SO4 (catalyst)?
A. C6H5CH2CH2OH
B. C6H5CH2C00-Na+ + CO2 + H20
C. C6H5CH2C00-NH4
D. C6H5CH2CO2CH3 + H20

Answer 10

D. C6H5CH2CO2CH3 + H20

Question 11

In the deacetylation of acetyl histone, what is
the reactant equation?
A. Histone - (CH2) 4-NH3+ +-CH3-COOO
Acetylation→ Histone – (CH2) 4-NH-C-CH3
B. all of these
C. Histone - (CH2)4-NH3++CH3 - COO
acetylation<Histone -(CH2)4-NH-CH ->
Deacetylation
D. 2 Histone- (CH2)4-NH3++4 CH3-COO -> 4
Histone- (CH2) 4-2NHO-

Answer 11

C. Histone - (CH2)4-NH3++CH3 - COO
acetylation<Histone -(CH2)4-NH-CH ->
Deacetylation

Question 12

Who among the following constituted
the concept of resonance in order to take
explain the structures of molecules or
ions that are not accounted for by the
octet rule?
A: August Kekule B: Linus Pauling
C: Gilbert Lewis D: Robert Robinson

Answer 12

B: Linus Pauling

Question 13

Define the relationship between the
number of electrons in the valence shell
and the number of covalent bonds it
forms: a.) Carbon, b.) Nitrogen, c.)
Oxygen, and d.) Hydrogen:
A: C = 4 electrons; 4 bonds
N = 5 electrons; 3 bonds
O = 6 electrons; 2 bonds
H = 2 electrons; 2 bonds
B: C = 5 electrons; 2 bonds
N = 6 electrons; 4 bonds
O = 3 electrons; 1 bonds
H = 2 electrons; 3 bonds
C: C = 6 electrons; 3 bonds
N = 4 electrons; 2 bonds
O = 2 electrons; 1 bonds
H = 2 electrons; 1 bonds
D: C = 2 electrons; 4 bonds
N = 3 electrons; 3 bonds
O = 2 electrons; 2 bonds
H = 4 electrons; 3 bonds

Answer 13

A: C = 4 electrons; 4 bonds
N = 5 electrons; 3 bonds
O = 6 electrons; 2 bonds
H = 2 electrons; 2 bonds

Question 14

4. Which among the following statements
   highlights the actual difference between
   Lewis Structures and Resonance
   A: Lewis structures shows how the atoms
   of a molecule are bonded to one another
   while the resonance represents the
   different substituent combinations
   B: Lewis structures focuses on the
   localization of electrons while resonance
   features the electrons capacity of being
   delocalized among the atoms
   C: Resonance structures represent the
   various ways in which a molecule can be
   drawn while the Lewis structure
   represents the accepted “True” structure
   of the molecule
   D: A resonance structure and Lewis
   structure are virtually indistinguishable
   from one another

Answer 14

B: Lewis structures focuses on the
localization of electrons while resonance
features the electrons capacity of being
delocalized among the atoms

Question 15

5. Determine whether each of the
   following statements pertaining to
   constitutional isomers is TRUE or FALSE.
   [a.] They have the same molecular formula
   [b.] They have the same molecular weight
   [c.] They have the same connectivity to
   their atoms
   [d.] They have the same physical
   properties
   A: T, F, F, F B: T, T, F, F
   C: F, T, T, T D: T, F, T, F

Answer 15

B: T, T, F, F

Question 16

Which among the following represents
the impact of Odd Hassel’s work in the
field of Organic Chemistry?
A: The difference between Eclipsed
Conformation and Staggered Conformation
observed in alkanes
B: The chair conformation of cyclohexane
C: The measurement of the dihedral angle
observed in gauche conformation
D: The identification of the various
sources of strain a cyclohexane may
experience

Answer 16

B: The chair conformation of cyclohexane

Question 17

Which among the following statements
best describe the most stable
conformation of 1-isopropyl-3-
methylcyclohexane?
A: The methyl substituent is attached in
the equatorial position at C3 and is
trans to the isopropyl substituent at C1
B: The isopropyl substituent is attached
in the equatorial position at C1 and is
trans to the methyl substituent at C3
C: The methyl substituent is attached in
the axial position in C3 and is cis to
the isopropyl substituent at C1
D: The isopropyl substituent is attached
in the axial position at C1 and is cis to
the methyl substituent at C3

Answer 17

B: The isopropyl substituent is attached
in the equatorial position at C1 and is
trans to the methyl substituent at C3

Question 18

15. Which has a higher absolute entropy
    at a temperature of 25 deg C,
    cyclopropane or propylene? Why?
    A: Both have the same absolute entropy at
    normal temperature
    B: Propylene due to the free rotation
    around the carbon-carbon single bond
    C: Cyclopropane due to the free rotation
    around the carbon-carbon double bond
    D: None of these

Answer 18

B: Propylene due to the free rotation
around the carbon-carbon single bond

Question 19

Which among the following statements
is true regarding the boiling point and
density of an unsubstituted alkane and a
halogen-substituted alkane?
A:Both the boiling point and density of a
halogen-substituted alkane is larger than
that of its unsubstituted alkane
counterpart.
B: Both the boiling point and density of
an unsubstituted alkane is larger than
that of its halogen-substituted alkane
counterpart.
C: The boiling point of an unsubstituted
alkane is larger than its halogen
substituted counterpart but their density
are equal.
D: The density of a halogen substituted
alkane is larger than that of its
unsubstituted alkane counterpart but
their boiling points are the same.

Answer 19

A:Both the boiling point and density of a
halogen-substituted alkane is larger than
that of its unsubstituted alkane
counterpart.

Question 20

Which among the following compounds
will rapidly react with hydrogen bromide
in order to form its corresponding alkyl
bromide?
A: 2-methylbutane B: 2-butanol
C: Cyclohexanol D: 1-ethylcyclopentanol

Answer 20

D: 1-ethylcyclopentanol

Question 21

How is a carbocation stabilized by
the alkyl groups attached to it?
A: The alkyl groups release an electron
density on the positively charged carbon
in order to disperse the positive charge
B: The electrons that are sigma to the
positively charged carbon has its orbital
overlap with the vacant p orbital of the
positively charged carbon
C: The leaving group transfers some of
its electrons to the carbocation in order
to disperse the positive charge
D: The electrons in the alpha-Carbon
hydrogen bonds greatly distributes the
positive charge as opposed to the betacarbon hydrogen bonds

Answer 21

A: The alkyl groups release an electron
density on the positively charged carbon
in order to disperse the positive charge

Question 22

Determine the degree of unsaturation
of the following organic molecules: [a]
C40H56, [b] C10H16O2, [c] C7H9Br, [d]
C4H8BrN
A: [a] DoU = 9 [b] DoU = 2
[c] DoU = 11 [d] DoU = 2
B: [a] DoU = 6 [b] DoU = 1
[c] DoU = 7 [d] DoU = 4
C: [a] DoU = 13 [b] DoU = 3
[c] DoU = 3 [d] DoU = 1
D: [a] DoU = 8 [b] DoU = 5
[c] DoU = 11 [d] DoU = 2

Answer 22

C: [a] DoU = 13 [b] DoU = 3
[c] DoU = 3 [d] DoU = 1

Question 23

Which among the following reagents
will not synthesize cyclohexanol if the
starting material is cyclohexene?
A: [1] Diborane, [2] Hydrogen Peroxide,
Sodium Hydroxide
B: Bromine and Water
C: Water with Sulfuric Acid
D: [1] 9-BBN, [2] Basic Hydrogen Peroxide

Answer 23

B: Bromine and Water

Question 24

Which among the following organic
compounds will be produced when 2,4-
dimethyl-3-pentanol is heated to 120 deg
C in the presence of sulfuric acid?
A: 2,4-dimethyl-1 pentene
B: 2,4-dimethyl-2-pentene
C: Both A and B
D: Neither A and B

Answer 24

C: Both A and B

Question 25

Which among the following sequence of
organic reactions will produce 1-bromo-2-
propanol if the starting material for the
synthesis is 2-propanol
A: [1] H2SO4, heat [2] B2H6, diglyme [3]
basic H2O2
B: [1] H2SO4, heat [2] Br2, H2O
C: [1] H2SO4, heat [2] Peroxyacetic acid
D: Synthesis is not feasible with the
given starting material

Answer 25

B: [1] H2SO4, heat [2] Br2, H2O

Question 26

A chemical engineering student is
studying the reaction mechanism of a
certain compound V. In one of the runs,
compound V was dissolved in methanol and
subsequently reacted with ozone, forming
compound W. Compound W later underwent
reduction through a reaction with
dimethyl sulfide forming Acetone and
Acetaldehyde. Identify Compound V.
A: 3-methyl-2-butene B: 2-methyl-1-butene
C: 3-methyl-1-butene D: 2-methyl-2-butene

Answer 26

D: 2-methyl-2-butene

Question 27

Who among the following proposed the
idea correlating Molecular Geometry and
Valence Electron Pairs that would later
become the Valence Shell Electron Pair
Repulsion (VSEPR) Theory?
A: Nevil Sidgwick B: Ronald Nyholm
C: Herbert Powell D: Ryutaro Tsuchida

Answer 27

B: Ronald Nyholm

Question 28

Linus Pauling introduced the concept
of hybridization of orbitals in order to
take into account the known geometries of
certain compounds, which did not include
____.
A: H2O B: NH3 C: CH4 D: H2S

Answer 28

D: H2S

Question 29

Determine whether each of the
following statements is TRUE or FALSE
[a] A molecule containing a stereogenic
center automatically indicates that it is
a chiral molecule
[b] A molecule with two chirality
centers, having an R,S configuration
respectively has an enantiomer whose
chirality centers have an R,R
configuration
[c] A molecule with an S configuration
for its single chirality center is bound
to display a Levorotatory response when
placed in a polarimeter
A: T, T, T B: T, F, T
C: F, T, F D: F, F, F

Answer 29

D: F, F, F

Question 30

A sample of cholesterol, weighing
70.5 mg was submitted to the laboratory
to analyze its optical activity. The
sample was dissolved in 300 mL of
chloroform before placing it in a 25 cm
sample tube and inserting it into the
polarimeter, installed with a newly
bought sodium lamp. If the observed
rotation of the plane-polarized light is
zero degrees, which among the following
is the identity of the sample?
A:100% (+)-cholesterol
B:100% (-)-cholesterol
C:50% (+)-cholesterol,50% (-)-cholesterol
D:None of the above

Answer 30

C:50% (+)-cholesterol,50% (-)-cholesterol