Download Organic Chemistry (HL) Revision Questions

International School of Johannesburg
Diploma Chemistry
Organic Chemistry (HL) Revision Questions
1.
The compounds H2NCH2CH2NH2 and HOOCCH2COOH react to form a polymer. What is the
structure of the repeating unit of the polymer?
A.
( HNCH2CONHCH2CH2NHCO )
B.
( HNCH2CH2NHCOCH2CO )
C.
( OCCH2CONHCH2NHCO )
D.
( HNCH2CH2NHCOCH2NH )
(Total 1 mark)
2.
Which two molecules are cis-trans isomers of each other?
A.
X and Z
B.
X and Y
C.
W and Y
D.
W and Z
(Total 1 mark)
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3.
What product is formed when CH3CH(OH)CH3 is reacted with acidified potassium
dichromate(VI)?
A.
CH3COOCH3
B.
CH3CH2CHO
C.
CH3CH2COOH
D.
CH3COCH3
(Total 1 mark)
4.
Benzene, C6H6, is a planar compound which differs from the non-planar structure of
cyclohexane, C6H12. The structures of benzene and the most stable form of cyclohexane are
represented below.
(a)
With reference to the compounds benzene, cyclohexane and 1,3-cyclohexadiene, state
which compound would contain the shortest carbon-carbon bond length.
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(1)
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(b)
Explain why it is more common for benzene to undergo substitution reactions than
addition reactions.
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(1)
(Total 2 marks)
5.
Halogenoalkanes can undergo SN1 and SN2 reactions with aqueous sodium hydroxide.
Which halogenoalkane will react fastest with a 0.1 mol dm–3 solution of aqueous sodium
hydroxide?
A.
2-chloro-2-methylpropane
B.
2-iodo-2-methylpropane
C.
1-chlorobutane
D.
1-iodobutane
(Total 1 mark)
6.
Propanitrile can be prepared by reacting bromoethane with potassium cyanide. Which statement
is not correct about the reaction between bromoethane and potassium cyanide?
A.
The reaction is bi-molecular.
B.
The reaction follows the SN2 mechanism.
C.
Homolytic fission occurs between the carbon-bromine bond in bromoethane.
D.
The cyanide ion, :CN–, acts as a nucleophile.
(Total 1 mark)
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7.
Which organic molecule is not a structural isomer of pentan-1-ol?
A.
pentan-2-ol
B.
2-methylpentan-2-ol
C.
2-methylbutan-2-ol
D.
pentan-3-ol
(Total 1 mark)
8.
Propan-1-ol and propan-2-ol are two structural isomers of C3H8O.
(i)
State the equation for the complete combustion of C3H8O.
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(2)
(ii)
Both propan-1-ol and propan-2-ol can be oxidized in aqueous solution by potassium
dichromate(VI). State any necessary conditions for the oxidation to occur and describe
the colour change during the oxidation process.
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(3)
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(iii)
State the name(s) and structure(s) of the organic product(s) that can be formed when each
of the alcohols is oxidized and suggest why one of the alcohols gives two organic
products and the other only gives one organic product.
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(5)
(Total 10 marks)
9.
(i)
Describe a chemical test that could be used to distinguish between propane and propene.
In each case state the result of the test.
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(2)
(ii)
Under certain conditions propene can polymerize to form poly(propene). State the type of
polymerization taking place and draw a section of the polymer to represent the repeating
unit.
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(2)
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(iii)
Other than polymerization, state one reaction of alkenes which is of economic
importance.
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(1)
(Total 5 marks)
10.
Which is the best definition of structural isomers?
A.
Compounds which have atoms with the same atomic numbers but different mass numbers
B.
Compounds which have the same general formula but differ by a CH2 group
C.
Compounds which have the same empirical formula but different molecular formulas
D.
Compounds which have the same molecular formula but different arrangements of atoms
(Total 1 mark)
11.
Which structure could represent a repeating unit of a polymer formed from propene?
A.
( CH2–CH(CH3) )
B.
( CH2–CH2–CH2 )
C.
( CH(CH3)–CH(CH3) )
D.
( CH2–CH2 )
(Total 1 mark)
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12.
What is the correct order of reaction types in the following sequence?
I C H OH →
II C H COOH 
III
C3H7Br →
→ C2H5COOC2H5
3 7
2 5
I
II
III
A.
substitution
oxidation
condensation
B.
addition
substitution
condensation
C.
oxidation
substitution
condensation
D.
substitution
oxidation
substitution
(Total 1 mark)
13.
Which substances are possible products of the incomplete combustion of octane?
A.
Carbon dioxide and hydrogen gas
B.
Carbon monoxide and water vapour
C.
Carbon monoxide and hydrogen gas
D.
Methane and hydrogen gas
(Total 1 mark)
14.
There are several structural isomers with the molecular formula C5H11Br.
(a)
Deduce the name of one of the isomers which can exist as enantiomers and draw
three-dimensional representations of its two enantiomers.
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(3)
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(b)
All the isomers react when warmed with a dilute aqueous solution of sodium hydroxide
according to the equation below.
C5H11Br + NaOH → C5H11OH + NaBr
(i)
The reaction with 1-bromopentane proceeds by an SN2 mechanism. Describe this
mechanism using structural formulas and curly arrows to represent the movement
of electron pairs.
(3)
(ii)
The reaction with 2-bromo-2-methylbutane proceeds by an SN1 mechanism.
Describe this mechanism using structural formulas and curly arrows to represent
the movement of electron pairs.
(3)
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(iii)
Explain why 1-bromopentane reacts by an SN2 mechanism whereas
2-bromo-2-methylbutane reacts by an SN1 mechanism.
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(3)
(iv)
Explain whether the boiling point of 1-bromopentane will be higher, lower or the
same as that of 2-bromo-2-methylbutane.
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(3)
(v)
The product C5H11OH formed from the reaction with 1-bromopentane is warmed
with ethanoic acid in the presence of a few drops of concentrated sulfuric acid.
State the name of the type of reaction taking place and the structural formula of the
organic product.
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(2)
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(c)
If the conditions of the reaction in (b) are changed so that a hot solution of sodium
hydroxide in ethanol is used then a different reaction occurs. The reaction with
2-bromo-2-methylbutane gives two different organic products. State the type of reaction
taking place and suggest the identity (name or structure) of these two products.
Explain whether or not they can exist as geometrical isomers.
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(4)
(Total 21 marks)
15.
Dihalogenoalkanes can react with warm dilute potassium hydroxide solution to form diols.
These diols can react with dicarboxylic acids.
(i)
Deduce the equation for the reaction of benzene-1,4-dicarboxylic acid with the diol
formed from 1,5-dibromopentane.
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(3)
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(ii)
Outline the economic importance of the reaction of diols with dicarboxylic acids.
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(1)
(Total 4 marks)
16.
Which is the correct classification of these alcohols?
1
2
1
2
3
3
A.
tertiary
secondary
primary
B.
tertiary
primary
secondary
C.
tertiary
tertiary
secondary
D.
secondary
primary
secondary
(Total 1 mark)
17.
Which of the structures below is an aldehyde?
A.
CH3CH2CH2CH2OH
B.
CH3CH2COCH3
C.
CH3CH2COOCH3
D.
CH3CH2CH2CHO
(Total 1 mark)
IB Questionbank Chemistry
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18.
Two compounds, A and D, each have the formula C4H9Cl.
Compound A is reacted with dilute aqueous sodium hydroxide to produce compound B with a
formula of C4H10O. Compound B is then oxidized with acidified potassium manganate(VII) to
produce compound C with a formula of C4H8O. Compound C resists further oxidation by
acidified potassium manganate(VII).
Compound D is reacted with dilute aqueous sodium hydroxide to produce compound E with a
formula of C4H10O. Compound E does not react with acidified potassium manganate(VII).
Deduce the structural formulas for compounds A, B, C, D and E.
A:
B:
C:
D:
E:
(Total 5 marks)
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19.
Deduce an equation for the reaction between propanoic acid and methanol. Identify the catalyst
and state the name of the organic compound, X, formed.
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(Total 4 marks)
20.
2-chloro-3-methylbutane reacts with sodium hydroxide via an SN2 mechanism.
Explain the mechanism by using curly arrows to represent the movement of electron pairs.
(Total 4 marks)
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