Isomerism: AQA A‑Level Chemistry questions

AQA A-Level Chemistry past-paper questions on 3.3.1.3 Isomerism, 2008–2025, with mark schemes and examiner’s reports where available.

All 113 questions on Isomerism, as a list

June 2025, Paper 2, Q02.1 (3 marks): Use IUPAC rules to name L. Explain why L exists as stereoisomers. [3 marks] Name Explanation
June 2025, Paper 2, Q02.2 (2 marks): Compound M has the same carbon chain as L but the double bond is in a different position. M also exists as stereoisomers. Draw the structural formula of M. Expl
June 2025, Paper 3, Q06.1 (1 mark): State the type of stereoisomerism shown in Branch A. [1 mark]
June 2025, Paper 3, Q06.2 (3 marks): Q can be reacted with methanol to form three different esters. State the number used to identify the position of the C=C bond in the name of the ester formed fr
June 2025, AS Paper 2, Q04.1 (2 marks): Compounds A and B • each have the molecular formula C4H6O2 • are functional group isomers of each other • each react with sodium carbonate to form a gas. Compou
June 2025, AS Paper 2, Q12 (1 mark): What is the name of this compound according to IUPAC rules? [1 mark] A E–3-fluoro-2-methylpent-3-ene B Z–3-fluoro-2-methylpent-4-ene C E–3-fluoro-4-methylpent-2
June 2024, Paper 3, Q25 (1 mark): Compound Y has the structural formula CH3COOCH2CH(CH3)2 Which compound is a position isomer of Y? [1 mark] A 5-hydroxyhexan-3-one B butyl ethanoate C hexanoic a
June 2024, Paper 3, Q26 (1 mark): Which compound shows E–Z isomerism? [1 mark] A 2,3-dimethylbut-1-ene B 2,3-dimethylbut-2-ene C 2-methylpent-2-ene D 3-methylpent-2-ene
June 2024, AS Paper 2, Q04.1 (6 marks): Compound J is one of a pair of stereoisomers. Explain: • what stereoisomers are • how E-Z stereoisomerism occurs • how the Cahn-Ingold-Prelog rules can be used
June 2023, Paper 3, Q02.1 (1 mark): Draw the displayed formula of an unbranched position isomer of pentan-2-ol that can be dehydrated to form a single alkene. [1 mark]
June 2023, Paper 3, Q02.2 (1 mark): Draw the skeletal formula of a chain isomer of pentan-2-ol that can be dehydrated to form a mixture of alkenes. [1 mark]
June 2023, Paper 3, Q02.3 (1 mark): Draw the structure of an unbranched functional group isomer of pentan-2-ol. [1 mark]
June 2023, Paper 3, Q02.4 (1 mark): Another isomer of pentan-2-ol is an alcohol that is not dehydrated when heated with concentrated sulfuric acid. Draw the structure of this isomer. [1 mark]
June 2023, AS Paper 2, Q18 (1 mark): Which is the IUPAC name for this compound? [1 mark] A E-3-fluorohex-3-ene B E-4-fluorohex-3-ene C Z-3-fluorohex-3-ene D Z-4-fluorohex-3-ene
June 2022, Paper 2, Q03.3 (1 mark): Draw the skeletal formula of a functional group isomer of 2-methylbut-1-ene. [1 mark]
June 2022, Paper 3, Q03.2 (2 marks): Define the term stereoisomers. [2 marks]
June 2022, Paper 3, Q03.3 (2 marks): Deduce the name of isomer A. Explain why A does not exhibit stereoisomerism. [2 marks] Name Explanation
June 2022, Paper 3, Q03.5 (2 marks): Deduce the name of isomer B and the name of isomer C. Explain the origin of the stereoisomerism in B and C. [2 marks] Names Explanation
June 2022, Paper 3, Q25 (1 mark): Which compound is an isomer of ethyl ethanoate? [1 mark] A butyl methanoate B methyl propanoate C methyl butanoate D propanoic acid
June 2022, AS Paper 2, Q03.1 (1 mark): Draw the displayed formula of a position isomer of hex-2-ene that exists as E and Z isomers. [1 mark]
June 2022, AS Paper 2, Q03.2 (1 mark): Draw the displayed formula of a chain isomer of hex-2-ene that does not exist as E and Z isomers. [1 mark] Butanal has the molecular formula C4H8O
June 2022, AS Paper 2, Q03.3 (1 mark): Draw the skeletal formula of a functional group isomer of butanal that has an absorption in the range 1680–1750 cm–1 in its infrared spectrum. [1 mark]
June 2022, AS Paper 2, Q03.4 (1 mark): Draw the skeletal formula of a structural isomer of butanal that has an absorption in the range 3230–3550 cm–1 in its infrared spectrum. [1 mark]
November 2021, Paper 2, Q06.3 (2 marks): Draw the E and Z forms of a structural isomer of C5H10O that shows both optical and geometric isomerism. [2 marks] E isomer Z isomer
November 2021, Paper 2, Q06.4 (2 marks): Isomer J is cyclic and has an ether functional group (C–O–C) Isomer J has only three peaks in its 13C NMR spectrum. Isomer J Draw two other cyclic isomers of C5
November 2021, Paper 3, Q23 (1 mark): Which compound has E–Z isomers? [1 mark] A CH2=CHBr B CH2=CBr2 C CHBr=CHBr D CBr2=CHBr
November 2021, AS Paper 2, Q09 (1 mark): Which alkene shows E–Z isomerism? [1 mark] A 2,3-dimethylbut-2-ene B 4-methylpent-2-ene C methylpropene D pent-1-ene
November 2020, Paper 2, Q03.4 (1 mark): State the type of structural isomerism shown by isomers P, Q, R and S. [1 mark]
November 2020, Paper 3, Q22 (1 mark): Which has E-Z isomers? [1 mark] A C2H2Br2 B C2H3Br C C2H4Br2 D C2H5Br
November 2020, AS Paper 2, Q05 (6 marks): Explain the differences between structural isomerism and stereoisomerism. Use examples to show how compounds with the molecular formula C4H8 exhibit stereoisome
June 2019, Paper 2, Q03.3 (2 marks): A second polymer in the mixture has a repeating unit with the structure shown. The third polymer in the mixture is a stereoisomer of this polymer. Draw the stru
June 2019, Paper 2, Q11.3 (2 marks): The compound C19H34O2 is the methyl ester of Z,Z-octadeca-9,12-dienoic acid. Part of the structure of the acid is shown. Complete the skeletal formula to show t
June 2019, AS Paper 2, Q13 (1 mark): Which compound is not an isomer of the following compound? [1 mark] A CH3CH2COCH3 B CH3CH═CHCH2OH C (CH3)2CHCHO D CH2═CHCH2CHO
June 2019, AS Paper 2, Q14 (1 mark): How many isomers are there of C3H9N? [1 mark] A 2 B 3 C 4 D 5
June 2019, AS Paper 2, Q17 (1 mark): Which statement is not correct about CH2═C(CH3)CH2Br? [1 mark] A It displays E-Z isomerism. B It forms an addition polymer. C It reacts with electrophiles. D It
June 2018, Paper 2, Q03.6 (2 marks): A pair of stereoisomers is also formed in the reaction in Question 03.5. Name the less polar stereoisomer formed. Explain how this type of stereoisomerism arise
June 2018, Paper 2, Q10.2 (2 marks): There are three secondary amines that contain four carbon atoms per molecule. Draw the skeletal formulas of these three secondary amines. [2 marks]
June 2018, Paper 3, Q28 (1 mark): How many structural isomers with the molecular formula C5H10O react with Tollens’ reagent? [1 mark] A 3 B 4 C 5 D 6
June 2018, AS Paper 2, Q15 (1 mark): How many structural isomers with an unbranched carbon chain have the molecular formula C4H8Br2? [1 mark] A 4 B 5 C 6 D 7
June 2017, Paper 2, Q10.1 (1 mark): Give the full IUPAC name of isomer P. [1 mark
June 2017, Paper 3, Q02.5 (3 marks): Butan-2-ol reacts with concentrated sulfuric acid to form a mixture of three isomeric alkenes. Two of the alkenes are stereoisomers. Draw the skeletal formula o
June 2017, Paper 3, Q24 (1 mark): Which compound does not show stereoisomerism? [1 mark] A 1,2-dichloropropene B 1,2-dichloropropane C 1,3-dichloropropene D 1,3-dichloropropane
June 2017, AS Paper 2, Q03.1 (6 marks): Compounds A, B and C all have the molecular formula C5H10 A and B decolourise bromine water but C does not. B exists as two stereoisomers but A does not show st
June 2017, AS Paper 2, Q14 (1 mark): Which compound is a structural isomer of Z-but-2-ene? [1 mark] A butane B E-but-2-ene C cyclobutane D methylbut-2-ene
June 2017, AS Paper 2, Q18 (1 mark): How many structural isomers are there with the molecular formula C3H6BrCl? [1 mark] A 4 B 5 C 6 D 7
June 2016, AS Paper 2, Q07.1 (1 mark): The alkene 3-methylpent-2-ene (CH3CH=C(CH3)CH2CH3) exists as E and Z stereoisomers. Draw the structure of Z-3-methylpent-2-ene. [1 mark]
Specimen, Paper 2, Q03.6 (1 mark): 0
Specimen, Paper 2, Q04.5 (1 mark): Name the type of structural isomerism shown by C and D. [1 mark] 0 4 . 5
Specimen, Paper 3, Q24 (1 mark): How many isomers have the molecular formula C5H12? [1 mark] A 2 B 3 C 4 D 5 2 4
Specimen, Paper 3, Q26 (1 mark): How many structural isomers have the molecular formula C4H9Br? [1 mark] A 2 B 3 C 4 D 5 2 6
Specimen, Paper 3, Q31 (1 mark): How many secondary amines have the molecular formula C4H11N? [1 mark] A 2 B 3 C 4 D 5 3 1
June 2016, CHEM1 (old spec), Q4(b)(iv) (3 marks): Compound X has several isomers. The structure of X is repeated here. Draw the displayed formula of a chain isomer, a position isomer and a functional group isom
June 2016, CHEM2 (old spec), Q8(b) (5 marks): All three isomers of C5H10 contain the same functional group. Draw the displayed formula of pent-1-ene. Draw the structures of the pair of stereoisomers and giv
June 2015, CHEM1 (old spec), Q6(d)(iii) (1 mark): Draw the displayed formula of the functional group isomer of propene. [1 mark]
June 2015, CHEM2 (old spec), Q6(d)(i) (1 mark): Draw the structure of X. [1 mark]
June 2015, CHEM2 (old spec), Q6(d)(ii) (1 mark): Which of the following, A, B, C or D, represents the type of isomerism shown by X and propanal? Write the correct letter, A, B, C or D, in the box. [1 mark] A c
June 2014, CHEM4 (old spec), Q8(c) (5 marks): Draw the structure of each of the following isomers of C5H8O2 Label each structure you draw with the correct letter L, M, N, P or Q. L is methyl 2-methylpropeno
June 2014, CHEM1 (old spec), Q5(e) (2 marks): Give the IUPAC name for the following compound and state the type of structural isomerism shown by this compound and dodecane. [2 marks] IUPAC name Type of stru
June 2014, CHEM2 (old spec), Q7(a)(i) (2 marks): State the meaning of the term stereoisomers. [2 marks]
June 2014, CHEM2 (old spec), Q7(a)(ii) (1 mark): Draw the structure of the E stereoisomer of Isomer 1. [1 mark]
June 2013, CHEM4 (old spec), Q8(b)(i) (3 marks): Draw the structures of these three isomers. Label each structure as primary, secondary or tertiary. (3 marks)
June 2013, CHEM1 (old spec), Q2(a)(i) (2 marks): State the meaning of the term structural isomers.
June 2013, CHEM1 (old spec), Q2(a)(ii) (1 mark): Give the IUPAC name of the position isomer of but-1-ene. (1 mark)
June 2013, CHEM1 (old spec), Q2(a)(iii) (1 mark): Give the IUPAC name of the chain isomer of but-1-ene. (1 mark)
June 2013, CHEM1 (old spec), Q2(a)(iv) (1 mark): Draw the displayed formula of a functional group isomer of but-1-ene. (1 mark)
June 2013, CHEM2 (old spec), Q5(a)(iii) (1 mark): State the type of structural isomerism shown by these two alkenes. (1 mark)
June 2013, CHEM2 (old spec), Q9(a)(i) (1 mark): Draw the structure of (Z)-but-2-enenitrile. (1 mark)
June 2013, CHEM2 (old spec), Q9(a)(ii) (1 mark): Identify the feature of the double bond in the E and Z isomers that causes them to be stereoisomers. (1 mark)
January 2013, CHEM1 (old spec), Q4(g)(iii) (1 mark): The following compound Y is produced when X reacts with chlorine. Deduce how many other position isomers of Y can be formed. Write the number of other position
June 2012, CHEM4 (old spec), Q5(e)(i) (1 mark): Draw a structural isomer of X that is an ethyl ester. (1 mark)
June 2012, CHEM4 (old spec), Q5(e)(ii) (1 mark): Draw a structural isomer of X that is an amide and also a tertiary alcohol. (1 mark)
June 2012, CHEM1 (old spec), Q2(b)(i) (1 mark): Give the IUPAC name of the position isomer of X. (1 mark)
June 2012, CHEM1 (old spec), Q2(b)(ii) (1 mark): Draw the structure of a functional group isomer of X. (1 mark)
June 2012, CHEM2 (old spec), Q7(a)(ii) (2 marks): Draw structures for the E and Z stereoisomers of hex-3-ene. E isomer of hex-3-ene Z isomer of hex-3-ene (2 marks)
June 2012, CHEM2 (old spec), Q7(a)(iii) (2 marks): State the meaning of the term stereoisomers.
January 2012, CHEM4 (old spec), Q7(e)(i) (2 marks): State the meaning of the term stereoisomers.
January 2012, CHEM1 (old spec), Q3(b)(i) (1 mark): Deduce the number of structural isomers with molecular formula C6H14 Write the number in this box. (1 mark) (Space for working)
January 2012, CHEM1 (old spec), Q3(b)(ii) (1 mark): State one type of structural isomerism shown by the isomers of C6H14 (1 mark)
January 2012, CHEM2 (old spec), Q8(a) (1 mark): State the type of structural isomerism shown by but-1-ene and but-2-ene. (1 mark)
June 2011, CHEM1 (old spec), Q7(b) (2 marks): One of the structural isomers of pentane is 2,2-dimethylpropane. Draw the displayed formula of 2,2-dimethylpropane. State the type of structural isomerism shown
June 2011, CHEM1 (old spec), Q7(e) (3 marks): Pentane can react with chlorine as shown in the following equation. C5H12 + Cl2 C5H11Cl + HCl Calculate the percentage atom economy for the formation of C5H11Cl
June 2011, CHEM2 (old spec), Q3(f)(i) (1 mark): The hydrocarbon that is a chain isomer of methylpropene, but does not exhibit E–Z stereoisomerism. (1 mark)
June 2011, CHEM2 (old spec), Q3(f)(ii) (1 mark): The alcohol that is a position isomer of butan-2-ol. (1 mark)
June 2011, CHEM2 (old spec), Q6(b) (1 mark): State the type of structural isomerism shown by these three isomers. (1 mark)
June 2011, CHEM2 (old spec), Q6(c)(i) (1 mark): Draw the structure of (Z)-pent-3-en-2-ol. (1 mark)
June 2011, CHEM2 (old spec), Q6(c)(ii) (1 mark): Identify the feature of the double bond in (E)-pent-3-en-2-ol and that in (Z)-pent-3-en-2-ol that causes these two compounds to be stereoisomers. (1 mark)
January 2011, CHEM1 (old spec), Q6(c) (4 marks): The structure shown below is one of several structural isomers of octane. Give the meaning of the term structural isomerism. Name this isomer and state its empi
January 2011, CHEM2 (old spec), Q9(a)(iii) (1 mark): Draw the displayed formula of the position isomer of butan-1-ol. (1 mark)
January 2011, CHEM2 (old spec), Q9(a)(v) (1 mark): Draw the displayed formula of a functional group isomer of this aldehyde. (1 mark)
June 2010, CHEM4 (old spec), Q3(a)(iii) (1 mark): Give the full IUPAC name of compound B. (1 mark)
June 2010, CHEM1 (old spec), Q6(b)(i) (2 marks): State the meaning of the term structural isomerism. (2 marks)
June 2010, CHEM1 (old spec), Q6(b)(iii) (1 mark): Draw the structure of a functional group isomer of pent-1-ene. (1 mark)
June 2010, CHEM2 (old spec), Q6(a)(iii) (2 marks): Draw the displayed formula for the minor product Q and state the type of structural isomerism shown by P and Q. Displayed formula for Q Type of structural isome
June 2010, CHEM2 (old spec), Q6(a)(iv) (1 mark): Draw the structure of the (E)-stereoisomer of 3-methylpent-2-ene. (1 mark)
June 2010, CHEM2 (old spec), Q6(b)(ii) (1 mark): State the type of structural isomerism shown by R and S. (1 mark)
June 2010, CHEM2 (old spec), Q6(b)(iii) (1 mark): Name one possible compound which could be S. (1 mark)
January 2010, CHEM4 (old spec), Q5(b)(ii) (1 mark): One of the methyl esters in the mixture has the IUPAC name methyl (Z)-octadec-9-enoate. Draw two hydrogen atoms on the diagram below to illustrate the meaning o
January 2010, CHEM1 (old spec), Q4(e)(ii) (1 mark): State the type of structural isomerism shown by Q and the haloalkane shown below. (1 mark) H C Br H3C C Cl CH3 H C H Br SECTION B Answer all questions in the sp
January 2010, CHEM2 (old spec), Q1(b)(ii) (1 mark): State the type of stereoisomerism shown by oleic acid. (1 mark)
January 2010, CHEM2 (old spec), Q6(a) (1 mark): State the type of structural isomerism shown by propanal and propanone. (1 mark)
January 2010, CHEM2 (old spec), Q9(a) (3 marks): Two of these are butan-l-ol (CH3CH2CH2CH2OH) and butan-2-ol. The other two isomers are alcohol X and alcohol Y. Draw the displayed formula for butan-2-ol. Alcoh
June 2009, CHEM1 (old spec), Q4(b)(ii) (2 marks): 4 (b) (ii) Explain why 2,2-dichloro-3-methylpentane is a structural isomer of 2,2-dichlorohexane. (2 marks)
June 2009, CHEM2 (old spec), Q7(c)(i) (2 marks): 7 (c) (i) State what is meant by the term stereoisomers. (2 marks)
June 2009, CHEM2 (old spec), Q7(c)(ii) (1 mark): 7 (c) (ii) Draw the structure of (E)-but-2-ene. (1 mark)
January 2009, CHEM1 (old spec), Q6(f) (3 marks): H3C C H H CH3 CH3 C H C CH3 CH3 6 (f) The molecular formula C8H18 represents several structural isomers. State what is meant by the term structural isomers. Nam
June 2008, CHM3W (2008 spec), Q2(b) (1 mark): 2 (b) Name the type of structural isomerism shown by these isomers. (1 mark)
June 2008, CHM3W (2008 spec), Q5(d) (2 marks): 5 (d) Draw the structure of an alkene which is an isomer of Q and which shows stereoisomerism. State the type of stereoisomerism shown by this isomer. Structure
June 2008, CHM6W (2008 spec), Q10 (1 mark): 10 Which one of the statements about the following ester is correct? A It is a chain isomer of pentanoic acid. B It is a functional group isomer of ethyl propan
June 2008, CHM6W (2008 spec), Q17 (1 mark): 17 The compound CF3CHBrCl is a general anaesthetic called halothane. The number of structural isomers, including halothane, having the molecular formula C2HBrCl
June 2008, CHM6W (2008 spec), Q38 (1 mark): 38 Functional group isomers include 1 CH3CH2CHBrCH3 and CH3CH2CH2CH2Br 2 CH3CH2COOH and HCOOCH2CH3 3 CH3CH2CH(NH2)COOH and H2NCH2CH2CH2COOH 4 CH3CH2OCH2CH3 and
January 2008, CHM3W (2008 spec), Q2(c) (1 mark): (c) Draw the structure of the position isomer of pent-1-ene. (1 mark)
January 2008, CHM3W (2008 spec), Q3(a)(i) (2 marks): (i) State what is meant by the term stereoisomers. (2 marks)
January 2008, CHM3W (2008 spec), Q3(a)(ii) (1 mark): (ii) State the type of stereoisomerism shown by geraniol and nerol. (1 mark)

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