Organic Chemical Pathways
Chemistry 3 & 4, Chapter 7
Multiple Choice
Identify the choice that best completes the statement or answers the question.
1.When a mixture of ethane gas and chlorine gas is exposed to UV light, a number
of products are detected, which can be separated by fractional distillation.
Besides various chloroethanes, what other product will be present?
A CH3Cl
B CH4
C HCl
D H2
2.Which of the following compounds could NOT be used as a starting material for
the synthesis of CH3CH2CH(OH)CH3?
I CH3CH2CH2CH2Cl
II CH3CH2CHClCH3
III CH3CH2CH=CH2
IV CH3CH=CHCH3
A II only
B I or II
C II or III
D II, III or IV
3.When propane, C3H8, undergoes cracking, which one of the following products
will NOT be obtained?
A CH4
B C2H2
C H2
D C4H10
4.Which one of the following amino acids is LEAST likely to be obtained from the
hydrolysis of a protein in food?
A NH2CH2CH(CH3)COOH
B NH2CH(CH3)COOH
C NH2CH2COOH
D NH2CH(SH)COOH
5.Which molecule is always produced when triglycerides undergo hydrolysis?
A CH2(CH2)14COOH
B C6H12O6
C C3H8O3
D H2O
6.When a mixture of pentane and pent-2-ene, which are both colourless liquids, is
mixed with liquid bromine, the red–brown colour of the bromine disappears.
Which one of the following is the correctly balanced equation for the reaction
that causes this colour change?
A C5H12(l) + Br2(l)  C5H12Br2(l)
B CH3CH2CH=CHCH3(l) + Br2(l)  CH3CH2CHBrCHBrCH3(l)
C CH3CH2CH2CH=CH2(l) + Br2(l)  CH3CH2CH2CHBrCH2Br(l)
D C5H10(l) + C5H12(l) + 2Br2(l)  2C5H10Br2(l) + H2(g)
7.A compound that is present in ‘red delicious’ apples, and yet smells like bananas,
is CH3COOCH2CH2CH2CH3. To synthesise this compound in the laboratory, you
would need to react:
A methanol and pentanoic acid.
B ethanol and butanoic acid.
C butan-1-ol and methanoic acid.
D butan-1-ol and ethanoic acid.
8.The molecular formula of glucose is C6H12O6 (Mr = 180.0 amu). If a disaccharide
is produced from two glucose monomers:
A its Mr will be 342.0 amu and it will contain an ester link.
B its Mr will be 360.0 amu and it will contain an ester link.
C its Mr will be 342.0 amu and it will contain a glycosidic link.
D its Mr will be 360.0 amu and it will contain a glycosidic link.
9.Aspartame, which is marketed as ‘Equal’ or ‘Nutrasweet’, is a sugar substitute
used in some low-calorie foods. The structure of Aspartame is shown below.
What functional groups are likely to have interacted to form the –CO–NH– link
at the centre of the molecule, if a H2O molecule was eliminated as this link
formed?
A –COOH and –NH2
B –COOH and –OH
C –OH and –NH2
D –COCl and –NH2
10What substance would be produced if you were to react 2-chloropentane with
.ammonia dissolved in ethanol?
A CH3CH(OH)CH2CH2CH3
B CH3CH2CH2CH(NH2)CH3
C CH3CH2CH2CH(OH)CH3
D NH2CH2CH2CH2CH2CH2NH2
11One of the major constituents of palm oil is palmitic acid, which has the formula
.CH3(CH2)14COOH. When this acid is reacted with potassium hydroxide, the
main constituent of a well-known soap is produced. What will be the other
product of the reaction?
A Glycerol
B Water
C Carbon dioxide
D An ester
12If you wish to commercially prepare ethanol from ethane derived from natural
.gas, you would:
A heat the ethane in NaOH solution, then distil off the ethanol.
B react the ethane with Cl2 gas under UV light, then add NaOH solution to
the product.
C add yeast organisms, let the mixture ferment then distil off the ethanol.
D dissolve the ethane in NaOH solution and then bubble O2 gas through the
mixture.
13To prepare CH3CH2CH2COOH, the reaction pathway would involve:
.A the oxidation of propan-1-ol
B the hydrolysis of prop-1-ene
C the oxidation of butan-1-ol
D an addition reaction between oxygen and but-1-ene
14Look at the following diagram.
.
Substances P, Q and R will be, respectively:
A C5H10, C5H10Br2, C5H12
B C5H11Cl, C5H11Br, C5H12
C C5H12, C5H10Br2, C5H10
D C5H12, C5H10Br2, C2H4
15A section of the structure of a polymer is shown below. To which of the
.following families of polymers would this belong?
–O–CH2–CH2–O–CO–CH2–CO–O–CH2–CH2–O–CO–CH2–CO–
A Polyamide
B Polyester
C Polysaccharide
D Protein
16Which of the following substances will be produced when CH3CH=CH2 is
.subjected to high pressure and temperature in the presence of certain catalysts
and undergoes a polymerisation reaction?
A –CH2CH2CH2CH2CH2CH2CH2CH2–
B –CH2CH3CH2CH2CH3CH2CH2CH3–
C –CH(CH3)CH2CH(CH3)CH2CH(CH3)CH2–
D –CH2OCOCH2CH2OCOCH2CH2OCOCH2–
17Ethanol can be produced industrially from propane that is derived from natural
.gas. The flow chart for this production is shown below:
Processes I, II and III are best described as, respectively:
A fractional distillation; reduction; hydrolysis
B fractional distillation; cracking; hydrolysis
C cracking; reduction; fermentation
D cracking; hydrogenation; oxidation
18Unsaturated fatty acids contain one or more C=C bonds. These can undergo an
.addition reaction with hydrogen, using a nickel catalyst. Which of the following
represents the molecular formula of a fatty acid that would react with hydrogen
in this way in a mole ratio of 1:1?
A C18H30O2
B C18H32O2
C C18H34O2
D C18H36O2
19The hydrogenation of alkenes is usually carried out in the presence of fine nickel
.wire mesh. Which of the following is NOT a role played by this mesh in this
reaction?
A Hold one of the gaseous reactants in place
B Lower the activation energy for the reaction
C Lower the temperature required for the reaction
D Slow down the reaction to make it safer and more easily controlled
20Examine the following protein segment.
.
How many different amino acids are present?
A 3
B 4
C 5
D 6
ANSWERS
1.When a mixture of
ethane gas and
chlorine gas is
exposed to UV
light, a number of
products are
detected, which can
be separated by
fractional
distillation. Besides
various
chloroethanes,
what other product
will be present?
ACH3Cl
B CH4
C HCl
DH2
C
ANSWER C
:
POINTS: 0 / 1
FEEDBA These
are
CK:
substitut
ion
reaction
s in
which
Cl
atoms
replace
H atoms
in the
molecul
e. The
displace
dH
atoms
combine
with Cl
atoms
that
result
from
splitting
up the
Cl2
molecul
es, to
produce
HCl.
pp202–3
REF:
2.Which of the following compounds could NOT be used as a starting
material for the synthesis of CH3CH2CH(OH)CH3?
I CH3CH2CH2CH2Cl
II CH3CH2CHClCH3
III CH3CH2CH=CH2
IV CH3CH=CHCH3
A II only
B I or II
C II or III
D II, III or IV
C
C
ANSWER: D
0/1
POINTS:
FEEDBACK:All the molecules have four C atoms as in the required
product, so none can be eliminated as possibilities on
this basis. In the case of I and II, since these are
saturated compounds, the OH can only replace the Cl
present, so will be located on the same C atom as the
Cl. This means that I will not produce the correct
structural isomer. In the case of III and IV, an addition
reaction across the C=C with H2O can attach an –OH
group to one of the C atoms involved in the double
bond, so theoretically both could yield the required
product in an hydrolysis reaction.
pp204, 211
REF:
3.When propane, C3H8, undergoes cracking, which one of the following
products will NOT be obtained?
A CH4
B C2H2
C H2
D C4H10
ANSWER: D
0/1
POINTS:
FEEDBACK:In the cracking process, a large molecule breaks up
into smaller parts. Some C3H8 molecules will break up
into C2H2 and CH4, and others will break up into C3H6
and H2. However, none will form larger molecules.
p235
REF:
4.Which one of the following amino acids is LEAST likely to be
obtained from the hydrolysis of a protein in food?
A NH2CH2CH(CH3)COOH
B NH2CH(CH3)COOH
C NH2CH2COOH
D NH2CH(SH)COOH
ANSWER: A
0/1
POINTS:
FEEDBACK:All of the compounds are amino acids, but only alphaamino acids can act as monomers for proteins. That is,
the amino functional group, –NH2, and the carboxyl
functional group, –COOH, must be attached to the
same carbon atom. In A, they are attached to two
different carbon atoms.
C
C
C
pp227–8
REF:
5.Which molecule is always produced when triglycerides undergo
hydrolysis?
A CH2(CH2)14COOH
B C6H12O6
C C3H8O3
D H2O
ANSWER: C
1/1
POINTS:
FEEDBACK:Molecules of triglycerides are built up from glycerol
and three fatty acids. A water molecule is eliminated as
each ester link forms as a result of a condensation
reaction between a hydroxyl group on the glycerol
molecule and the carboxyl group on each fatty acid
molecule. When a triglyceride undergoes hydrolysis,
the reverse reaction occurs and glycerol, C3H8O3, and
three fatty acids are produced. Answer A represents
only one possible fatty acid.
p216
REF:
6.When a mixture of pentane and pent-2-ene, which are both colourless
liquids, is mixed with liquid bromine, the red–brown colour of the
bromine disappears. Which one of the following is the correctly
balanced equation for the reaction that causes this colour change?
A C5H12(l) + Br2(l)  C5H12Br2(l)
B CH3CH2CH=CHCH3(l) + Br2(l)  CH3CH2CHBrCHBrCH3(l)
C CH3CH2CH2CH=CH2(l) + Br2(l) 
CH3CH2CH2CHBrCH2Br(l)
D C5H10(l) + C5H12(l) + 2Br2(l)  2C5H10Br2(l) + H2(g)
ANSWER: B
0/1
POINTS:
FEEDBACK:Bromine is only decolourised when it undergoes an
addition reaction with unsaturated hydrocarbons, such
as pent-2-ene. Hence the answer can only be B or C.
Only B has the correct structure for pent-2-ene. The
isomer reacting in C is pen-1-ene.
p211
REF:
7.A compound that is present in ‘red delicious’ apples, and yet smells
like bananas, is CH3COOCH2CH2CH2CH3. To synthesise this
compound in the laboratory, you would need to react:
A methanol and pentanoic acid.
B ethanol and butanoic acid.
C butan-1-ol and methanoic acid.
D butan-1-ol and ethanoic acid.
ANSWER: D
0/1
POINTS:
FEEDBACK:The start of the formula (CH3CO) contains two C
atoms and tells us that the acid from which this ester is
C
C
derived is ethanoic acid, CH3COOH. The last part of
the formula contains four C atoms and tells us that the
alcohol required is butan-1-ol, CH3CH2CH2CH2OH. If
this isomer is not present, the –OH functional group
will not be at the end of the molecule, which is where
it must be if the required ester is to be produced.
p213–4
REF:
8.The molecular formula of glucose is C6H12O6 (Mr = 180.0 amu). If a
disaccharide is produced from two glucose monomers:
A its Mr will be 342.0 amu and it will contain an ester link.
B its Mr will be 360.0 amu and it will contain an ester link.
C its Mr will be 342.0 amu and it will contain a glycosidic link.
D its Mr will be 360.0 amu and it will contain a glycosidic link.
ANSWER: C
1/1
POINTS:
FEEDBACK:The condensation reaction between two glucose
molecules results in the elimination of a H2O molecule
at the link, so its Mr = (360.0 – 18.0) amu = 342 amu.
The link present in disaccharides and polysaccharides
is the glycosidic link, also known as an ether link.
p230
REF:
9.Aspartame, which is marketed as ‘Equal’ or ‘Nutrasweet’, is a sugar
substitute used in some low-calorie foods. The structure of Aspartame
is shown below.
What functional groups are likely to have interacted to form the –
CO–NH– link at the centre of the molecule, if a H2O molecule was
eliminated as this link formed?
A –COOH and –NH2
B –COOH and –OH
C –OH and –NH2
D –COCl and –NH2
ANSWER: A
0/1
POINTS:
FEEDBACK:The –CO–NH– group may be an amide link or a
peptide link. But given that H2O was eliminated as the
link formed, we can deduce that it is a peptide link and
hence is formed as a result of a condensation reaction
between a carboxyl group, –COOH, on one molecule
(the first monomer) and an amine group, –NH2, on the
C
C
C
other.
p228
REF:
10.What substance would be produced if you were to react 2chloropentane with ammonia dissolved in ethanol?
A CH3CH(OH)CH2CH2CH3
B CH3CH2CH2CH(NH2)CH3
C CH3CH2CH2CH(OH)CH3
D NH2CH2CH2CH2CH2CH2NH2
ANSWER: B
0/1
POINTS:
FEEDBACK:This is the usual pathway by which an amine may be
prepared. Since this is a direct substitution reaction, the
starting chloroalkane must have the chloro group
attached to the same carbon atom as the one to which
the amino group is to be attached.
p203
REF:
11.One of the major constituents of palm oil is palmitic acid, which has
the formula CH3(CH2)14COOH. When this acid is reacted with
potassium hydroxide, the main constituent of a well-known soap is
produced. What will be the other product of the reaction?
A Glycerol
B Water
C Carbon dioxide
D An ester
ANSWER: B
0/1
POINTS:
FEEDBACK:Normally, reacting NaOH solution or KOH solution
with an oil will produce soaps (salts of the fatty acid
molecules) and glycerol. To make an ester, this fatty
acid would need to be reacted with an alcohol, not a
base. But in this case the products will be the soap,
CH3(CH2)14COOK, and H2O.
pp213–4, 216
REF:
12.If you wish to commercially prepare ethanol from ethane derived
from natural gas, you would:
A heat the ethane in NaOH solution, then distil off the ethanol.
B react the ethane with Cl2 gas under UV light, then add NaOH
solution to the product.
C add yeast organisms, let the mixture ferment then distil off the
ethanol.
D dissolve the ethane in NaOH solution and then bubble O2 gas
through the mixture.
ANSWER: B
0/1
POINTS:
FEEDBACK:Ethane is non-polar and hence will not react directly
with, or even dissolve in, NaOH solution. But by
converting the ethane to a chloroethane, it becomes
C
sufficiently polar to dissolve and react. The –OH group
then replaced the –Cl atom in the molecule. Yeast
organisms require a sugar, not an alkane, for
fermentation to occur.
pp195, 202–4
REF:
13.To prepare CH3CH2CH2COOH, the reaction pathway would involve:
A the oxidation of propan-1-ol
B the hydrolysis of prop-1-ene
C the oxidation of butan-1-ol
D an addition reaction between oxygen and but-1-ene
ANSWER: C
1/1
POINTS:
FEEDBACK:An alcohol is oxidised by an oxidant such as oxygen or
acidified potassium dichromate to its corresponding
carboxylic acid. Since the carboxylic acid contained
four C atoms in a straight chain, with the carboxyl
group at the end, we had to start with butan-1-ol.
p205
REF:
14.Look at the following diagram.
C
Substances P, Q and R will be, respectively:
A C5H10, C5H10Br2, C5H12
B C5H11Cl, C5H11Br, C5H12
C C5H12, C5H10Br2, C5H10
D C5H12, C5H10Br2, C2H4
ANSWER: A
0/1
POINTS:
FEEDBACK:Alkenes undergo an addition reaction with water,
hydrogen and bromine, so P is an alkene. Since it must
contain the same number of C atoms as the alcohol, it
can only be pentene. When H2O is added to C5H10, we
obtain C5H12O. This rearranges to C5H11OH, which
shows the hydroxyl group. Similarly the addition of
Br2 and H2 to C5H10 produces the formulas C5H10Br2
and C5H12 respectively.
pp209–11
REF:
C
C
C
15.A section of the structure of a polymer is shown below. To which of
the following families of polymers would this belong?
–O–CH2–CH2–O–CO–CH2–CO–O–CH2–CH2–O–CO–CH2–CO–
A Polyamide
B Polyester
C Polysaccharide
D Protein
ANSWER: B
0/1
POINTS:
FEEDBACK:The links shown are –O–CO–, which are ester links.
Hence it is a polyester. The monomers would be the
diol HO–CH2–CH2–OH and the dicarboxylic acid
HOOC–CH2–COOH.
pp223–4
REF:
16.Which of the following substances will be produced when
CH3CH=CH2 is subjected to high pressure and temperature in the
presence of certain catalysts and undergoes a polymerisation
reaction?
A –CH2CH2CH2CH2CH2CH2CH2CH2–
B –CH2CH3CH2CH2CH3CH2CH2CH3–
C –CH(CH3)CH2CH(CH3)CH2CH(CH3)CH2–
D –CH2OCOCH2CH2OCOCH2CH2OCOCH2–
ANSWER: C
1/1
POINTS:
FEEDBACK:Propene, CH3CH=CH2, undergoes an addition
polymerisation. This occurs across the double bond of
each monomer. The CH3 group attached to one of the
C atoms involved in the double bond then becomes a
side group in the polymer. Answer D can only be a
condensation polymer, since it contains ester links, and
can only form from monomers that have two
functional groups.
p222
REF:
17.Ethanol can be produced industrially from propane that is derived
from natural gas. The flow chart for this production is shown below:
Processes I, II and III are best described as, respectively:
A fractional distillation; reduction; hydrolysis
B fractional distillation; cracking; hydrolysis
C cracking; reduction; fermentation
D cracking; hydrogenation; oxidation
ANSWER:
POINTS:
B
0/1
C
C
FEEDBACK:Propane is separated from the other components of
natural gas (methane, ethane and butane) by fractional
distillation. Propane contains three carbon atoms and
ethene only contains two carbon atoms. The breaking
up of a larger hydrocarbon into a smaller one is termed
cracking. Water is added to ethene to convert it to
ethanol. This is an addition reaction, not a redox
reaction. The production of ethanol by fermentation
requires sugar and yeast organisms, not ethene.
pp195, 233–5
REF:
18.Unsaturated fatty acids contain one or more C=C bonds. These can
undergo an addition reaction with hydrogen, using a nickel catalyst.
Which of the following represents the molecular formula of a fatty
acid that would react with hydrogen in this way in a mole ratio of
1:1?
A C18H30O2
B C18H32O2
C C18H34O2
D C18H36O2
ANSWER: C
1/1
POINTS:
FEEDBACK:A saturated carboxylic acid, which will not undergo an
addition reaction with H2, contains only single C–C
bonds. This means that it will consist of an alkyl group
attached to the carboxyl group and it will have the
general formula CnH2n+1COOH. For an unsaturated
fatty acid to undergo an addition reaction with H2 in
the ratio 1:1, which means that one mol of the acid
reacts with one mol H2, it must have just one C=C
bond. Hence it will have two H atoms less than the
saturated acid; these will be added in when it reacts
with H2. Thus its general formula will be
CnH2n-1COOH. Of n =17, the formula of the acid will
be C17H33COOH, which rearranges to C18H34O2.
p209
REF:
19.The hydrogenation of alkenes is usually carried out in the presence of
fine nickel wire mesh. Which of the following is NOT a role played
by this mesh in this reaction?
A Hold one of the gaseous reactants in place
B Lower the activation energy for the reaction
C Lower the temperature required for the reaction
D Slow down the reaction to make it safer and more easily
controlled
ANSWER: D
0/1
POINTS:
FEEDBACK:The nickel gauze acts as a catalyst. It speeds up the
reaction by lowering the activation energy, which
means more particles have sufficient energy for a
successful collision, and helps ‘pin down’ one of the
reactants so the collision rate is greater. In addition, it
lowers the temperature required.
p210
REF:
20.Examine the following protein segment.
C
How many different amino acids are present?
A3
B 4
C 5
D6
ANSWER: B
0/1
POINTS:
FEEDBACK:We first break up the polymer into its monomers by
‘cutting’ through the peptide links. This produces six
monomers. However, two sets of monomers have the
same R group, so there are really only four different
amino acids present.
pp227–8
REF: