plumiChirality: Edexcel International A Level Chemistry questions
Every Edexcel International A Level Chemistry exam question on 15A Chirality (specification points 15.1–15.5), 2019–2025, with its mark scheme and examiner’s report.
Paper
All papers
Exam
All years
Calculations
Q20(a)(i)
The whole paper ↗Q19(a)(v)
The whole paper ↗Q16(a)
The whole paper ↗Your answerQ3(a)
The whole paper ↗Your answerQ19(a)(i)
The whole paper ↗Q19(a)(iii)
The whole paper ↗- Your answer
Q10(b)(ii)
The whole paper ↗Your answerQ17(b)
The whole paper ↗Q11(a)
The whole paper ↗Your answerQ18(b)(ii)
The whole paper ↗Q10(c)
The whole paper ↗Your answerQ15(a)(ii)
The whole paper ↗Q14(b)
The whole paper ↗- Your answer
- Your answer
Q25(e)
The whole paper ↗Q18(a)
The whole paper ↗Q19(c)(iv)
The whole paper ↗Q15(b)
The whole paper ↗
All 42 questions on Chirality, as a list
- June 2025, Unit 5, Q20(a)(i) (1 mark): Draw an asterisk (*) on the chiral carbon in phenylalanine. (1)
- June 2025 (A), Unit 5, Q19(a)(v) (3 marks): Alanine exists as two optical isomers. Explain how this type of isomerism occurs, stating how the isomers may be distinguished. (3)
- January 2025, Unit 5, Q16(a) (1 mark): Which compound is an optically active amino acid? (1) A compound W B compound X C compound Y D compound Z
- October 2024, Unit 4, Q3(a) (1 mark): How many chiral centres are present in nandrolone? (1) A six B seven C eight D nine
- October 2024, Unit 4, Q19(a)(i) (1 mark): State what is meant by the term stereoisomer. (1)
- October 2024, Unit 4, Q19(a)(iii) (3 marks): In one experiment, a single stereoisomer of 2‑bromobutane was hydrolysed. Explain the stereochemistry of the product of this reaction. (3)
- June 2024, Unit 4, Q8 (1 mark): How many chiral centres are in the molecule shown? O O A 4 B 5 C 6 D 7 Use this space for any rough working. Anything you write in this space will gain no credi
- June 2024, Unit 5, Q10(b)(ii) (1 mark): What is the maximum number of chiral centres in the dipeptides in (b)(i)? (1) A 0 B 1 C 2 D 3
- June 2024, Unit 5, Q17(b) (3 marks): One of the steps in the synthesis is shown. N H H N H H N H CN– / H+ Explain, with reference to the mechanism, why this step in the reaction sequence will not p
- January 2024, Unit 4, Q11(a) (1 mark): Carvone shows (1) A geometric and optical isomerism B geometric isomerism only C optical isomerism only D neither geometric nor optical isomerism
- January 2024, Unit 4, Q18(b)(ii) (3 marks): Explain why the 2‑hydroxypropanoic acid, CH3CH(OH)COOH, produced is not optically active. (3)
- January 2024, Unit 5, Q10(c) (1 mark): Which of the esters could rotate the plane of plane‑polarised monochromatic light? (1) A Q only B Q and R C Q, R and S D R and S
- January 2024, Unit 5, Q15(a)(ii) (2 marks): The OH group is shown attached to the carbon chain by a wedge‑shaped bond. Suggest why the bond between the carbon chain and the OH group is shown as a wedge. (
- October 2023, Unit 4, Q14(b) (2 marks): Explain why the product of the reaction is not optically active even though it contains a chiral carbon atom. (2)
- June 2023, Unit 4, Q5 (1 mark): Which pair of compounds can form a racemic mixture when mixed? CH2OH CH2OH A H H C2H5 CH2OH HO H3C CH2OH CH2OH B H H C2H5 C2H5 HO HO CH3 CH3 C H HO C2H4OH CH2OH
- June 2023, Unit 4, Q6 (1 mark): Metoprolol is a drug used to treat heart problems. The structure of metoprolol is shown. OH H O N CH3 CH3 H3C O How many chiral centres are there in a molecule
- June 2023, Unit 5, Q25(e) (1 mark): Articaine is a chiral molecule. Indicate any chiral centres on the structure of articaine. (1) O S O NH NH O articaine
- January 2023, Unit 4, Q18(a) (6 marks): Explain why lactic acid formed in muscles is optically active while lactic acid obtained using the laboratory synthesis is not. You should define any terms you
- January 2023, Unit 5, Q19(c)(iv) (1 mark): Circle the two chiral carbon atoms in aspartame on the structure shown. (1) NH2 O H N OH O O O
- October 2022, Unit 4, Q15(b) (2 marks): Lactic acid is a chiral molecule, existing as a pair of non-superimposable mirror images called enantiomers. Complete the 3D diagrams of the enantiomers of lact
- October 2022, Unit 4, Q15(c)(i) (1 mark): State what is meant by racemic lactic acid. (1)
- October 2022, Unit 4, Q15(c)(iv) (2 marks): Explain, with reference to your mechanism in (c)(ii), why the lactic acid formed in this process is racemic. (2)
- October 2022, Unit 5, Q21(c) (2 marks): Explain, using a diagram, which type of stereoisomerism is shown by coniine. In your diagram use R to represent the alkyl group. (2)
- June 2022, Unit 4, Q17(b)(ii) (1 mark): Describe how you could distinguish between pure samples of the two optical isomers. (1)
- June 2022, Unit 4, Q17(b)(iii) (2 marks): Explain, with reference to the reaction mechanism, why this reaction produces a racemic mixture. (2)
- June 2022, Unit 4, Q17(c)(ii) (1 mark): State why the product formed in (c)(i) does not show optical isomerism. (1)
- June 2022, Unit 6, Q4(b)(i) (1 mark): Identify the chiral carbon on the diagram. (1)
- June 2022, Unit 6, Q4(b)(ii) (2 marks): The limonene extracted from orange peel is D‑limonene. State how the presence of a single optical isomer could be confirmed, naming the apparatus used. No exper
- January 2022, Unit 4, Q8 (1 mark): Menthol has a number of medicinal uses. It can be extracted from the peppermint plant. The structure of menthol is OH How many chiral centres are there in one m
- January 2022, Unit 4, Q9 (1 mark): Which of these reactions does not result in the formation of a racemic mixture? A but‑2‑ene with HCl B but‑1‑ene with HCl C propanal with HCN D propanone with H
- January 2022, Unit 4, Q10 (1 mark): When a single enantiomer of 2‑iodobutane reacts with sodium hydroxide, the product is a mixture of enantiomers. This is because A the reaction is a nucleophilic
- January 2022, Unit 4, Q19(b) (2 marks): The organic products of this reaction are enantiomers. Draw the three‑dimensional structures of these enantiomers. (2)
- October 2021, Unit 4, Q10 (1 mark): Citronellol is found in rose and geranium oils. OH citronellol The type(s) of stereoisomerism shown by citronellol is A optical and geometric isomerism B optica
- June 2021, Unit 4, Q8(a) (1 mark): What is the number of chiral centres in a molecule of menthol? (1) A 1 B 2 C 3 D 4
- June 2021, Unit 4, Q13 (1 mark): How many optical isomers does this molecule have? Br OH Cl A 2 B 3 C 6 D 8
- June 2021, Unit 4, Q14 (1 mark): Which of these structures is not identical to the others? OH H3C OH OH Cl CH2CH3 C C C C Cl Cl CH2CH3 CH2CH3 Cl H3CH2C CH3 OH CH3 H3C Structure A Structure B St
- June 2021, Unit 4, Q19(a)(ii) (3 marks): A student predicted that the product of Step 1 would rotate the plane of plane-polarised light. Comment on this prediction. (3)
- January 2021, Unit 4, Q12 (1 mark): A sample of a bromoalkane, RBr, containing a single optical isomer reacts with hydroxide ions in an SN1 mechanism. RBr + OH− o ROH + Br− The alcohol formed is a
- January 2021, Unit 4, Q17(a)(i) (1 mark): The structure of lactic acid is H COOH COOH C HO HO CH CH3 Give a reason why lactic acid shows optical isomerism. (1)
- January 2021, Unit 4, Q17(a)(ii) (1 mark): A laboratory sample of lactic acid does not rotate the plane of plane-polarised monochromatic light. Give a reason for this observation. (1)
- October 2020, Unit 5, Q22(d) (1 mark): Phenylalanine is an amino acid that exists as optical isomers. The structure of one of the optical isomers is shown. Complete the diagram to show the other opti
- January 2020, Unit 4, Q2 (1 mark): Which of these molecules can rotate the plane of plane-polarised light? A H2NCH2COOH B HOCH2CH2COOH C ClCH2C(CH3)(Cl)COOH D H2NC(CH3)2COOH
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