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Organic synthesis (Module 6)

Past-paper questions pack

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Questions are numbered; the mark schemes (the answer key) follow on separate pages so the question pages can be handed out alone. www.chemistryaleveltutor.com

OCR AS and A-level Chemistry past-paper questions since 2016 · 56 parts · mark schemes follow the questions · www.chemistryaleveltutor.com · Questions and mark schemes © OCR

1. June 2025 · Paper 2 · Q14 · 1 marks ·
14 The structure of vitamin C is shown. HO OH OH O O OH Which reagent(s) will react with vitamin C? 1 Aqueous bromine water 2 Acidified potassium dichromate(VI) 3 Aqueous silver nitrate in ethanol A 1, 2 and 3 B Only 1 and 2 C Only 2 and 3 D Only 1 Your answer [1]
2. June 2025 · Paper 2 · Q22(b)(i) · 2 marks ·
Question 22(b) starts on Page 30 (b) This part is about compounds called β-keto acids. The equation shows the decomposition of a β-keto acid. O O O + CO2 OH (i) Draw the structures of the organic products you would expect from the decomposition of the two other β-keto acids below. O O OH O O OH [2]
3. June 2025 · Paper 2 · Q22(b)(ii) · 1 marks ·
(ii) α-Amino acids have the NH2 group bonded to the carbon atom adjacent to the carboxylic acid group. Suggest the difference between an α-keto acid and a β-keto acid. .......................................................................................................................................................... .......................................................................................................................................................... ..................................................................................................................................................... [1]
4. June 2025 · Paper 3 · Q5(a)(iv) · 4 marks ·
(iv) The mechanism for Step 2 in the reduction of C6H5COOC2H5 is shown below. In the mechanism, LiAl H4 can be represented as H–. Complete the mechanism by adding curly arrows to the three boxes. _ O O C6H5 C C6H5 C OC2H5 OC2H5 H– H O _ C6H5 C + OC2H5 H H– _ O _ C6H5 C H + OC2H5 H [4]
5. June 2024 · Paper 2 · Q20(d) · 4 marks ·
(d) The compound below contains an ester and an amide group. O N O H O Draw the structures of the organic products formed by the complete alkaline hydrolysis of this compound using NaOH(aq). [4]
6. June 2024 · Paper 2 · Q23(a) · 1 marks ·
23 Oil of wintergreen is a liquid used in medicine to relieve muscle pain. Compound H is a component in oil of wintergreen and can be synthesised from compound G, as shown below. The boiling point and density of compound H are stated. O O OH O OH OH Compound G Compound H boiling point = 222 °C density = 1.174 g cm−3 A student prepares a sample of compound H by the method below. Step 1 Reflux 8.97 g of compound G for 30 minutes with an excess of methanol in the presence of a small amount of sulfuric acid as a catalyst. Step 2 Add an excess of aqueous sodium carbonate, Na2CO3(aq). Two layers are obtained. Step 3 Purify the impure compound H that forms from the resulting mixture. The student follows this method and obtains 5.32 g of pure compound H. (a) Why does the student use reflux in Step 1? .......................................................................................................................................................... ..................................................................................................................................................... [1]
7. June 2023 · Paper 2 · Q4 · 1 marks · AO1
4 The structure of the painkiller paracetamol is shown below. OH O N H Paracetamol Which functional groups are present in paracetamol? A alcohol, amide B alcohol, arene, ketone, amine C phenol, amide D phenol, ketone, amine Your answer [1]
8. June 2023 · Paper 2 · Q18(c) · 3 marks · AO3
(c) Describe how to purify the impure crystals in Step 3. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................. [3]
9. June 2023 · Paper 2 · Q19 · 6 marks · AO3
19* A student intends to synthesise compound Z, as shown in the flowchart below. H H C Br C C H H H Stage 1 Intermediate 1 Stage 2 Intermediate 2 Stage 3 Br H H H H C C C C NH2 H H H H Compound Z Plan this synthesis showing reagents, the structures of intermediate 1 and intermediate 2, and equations. [6] .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... Additional answer space if required. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ..........................................................................................................................................................
10. June 2023 · Paper 2 · Q22(b) · 9 marks · AO1, 2
(b) Complete the flowchart by filling in each box. reagent(s) ................................... catalyst unsaturated alcohol ................................... diol (major product) reagent(s) ................................... H H reagent(s) C C ................................... H C O H acrolein carboxylic acid reagent(s) ................................... polymer (2 repeat units) acyl chloride [9]
11. June 2023 · Paper 3 · Q3 · 6 marks · AO3
3* A chemist is investigating compound A, shown below, as a potential organic intermediate. O OH CN Compound A Describe the type of stereoisomerism shown by compound A and suggest three reactions of compound A, one for each of the three functional groups using reagents of your choice. In your answer, show stereoisomers of compound A, your chosen reactants and conditions, and the structures for the organic products produced. Mechanisms and equations are not required. 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Additional answer space if required. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ..........................................................................................................................................................
12. June 2023 · Paper 3 · Q5(b)(ii) · 3 marks · AO2
(ii) In this reaction, 1 mol of aspirin reacts with 3 mol of hot NaOH(aq). Complete the equation for the reaction of aspirin with an excess of hot NaOH(aq). Show structures for organic compounds. O OH O + ......................... O [3]
13. June 2022 · Paper 2 · Q4 · 1 marks · AO1
4 The skeletal formula of an organic compound is shown below. N OH O Which functional groups are present? A amide and alcohol B amide and carboxylic acid C amine and carboxylic acid D amine, ketone and alcohol Your answer [1]
14. June 2022 · Paper 2 · Q16(c)(i) · 2 marks · AO3
(c) ‘Ozonolysis’ is used in organic synthesis. Ozone breaks C=C bonds to form carbonyl compounds. For example, the complete ozonolysis of methylbut-2-ene is shown below. H3C H H3C H O3 C C C O + O C H3C CH3 H3C CH3 (i) Draw the structures of the products you would expect from the ozonolysis of the two compounds below. [2]
15. June 2022 · Paper 2 · Q19(b) · 4 marks · AO2
(b) The structure of 2-hydroxybutanoic acid is shown below. H CH3CH2 C COOH OH 2-hydroxybutanoic acid Fill in the flowchart for reactions involving 2-hydroxybutanoic acid. C6H5COOH / H2SO4 (CH3)2CHOH / H2SO4 reflux reflux H H ............................... CH3CH2 C CN CH3CH2 C COOH OH OH 2-hydroxybutanoic acid NaBH4 [4]
16. June 2022 · Paper 2 · Q19(e) · 6 marks · AO3
(e)* A student intends to synthesise compound I. O O NH2 Compound I Plan a synthesis to prepare 9.36 g of compound I starting from 2-chloropropanoic acid, CH3CHCl COOH. The overall percentage yield of compound I from 2-chloropropanoic acid is 64%. In your answer, include starting mass of 2-chloropropanoic acid, reagents, conditions and equations where appropriate. [6] ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... Additional answer space if required. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ...................................................................................................................................................
17. June 2022 · Paper 2 · Q20(e) · 4 marks · AO2, 3
(e) 1-phenylethanol is a naturally occurring compound found in many vegetables and flowers. 1-phenylethanol can be synthesised from 2-phenylethanol in two stages. H H OH H Stage 1 Stage 2 C C OH Intermediate C C H H H H H 2-phenylethanol 1-phenylethanol Suggest reagents, conditions and equations for each stage in the synthesis. Show structures for organic compounds. Stage 1 reagents and conditions ........................................................................................................... equation: Stage 2 reagents and conditions ........................................................................................................... equation: [4]
18. November 2021 · Paper 2 · Q16(d)(ii) · 2 marks · AO3
(ii) Two more Diels-Alder reactions of buta-1,3-diene are shown below. In the boxes, draw the organic product of each reaction. O OCH3 + OCH3 O + [2]
19. November 2021 · Paper 2 · Q18(b) · 7 marks · AO1, 2
(b) Complete the flowchart for two synthetic routes to the amino acid valine. ester C7H14O3 .................................................. O HO OH .................................. C5H10O3 acyl chloride C5H9O2Cl .................................................. O H2N OH ........................................... valine haloalkane C5H11NO2 C5H9BrO2 [7]
20. November 2021 · Paper 2 · Q19(a)(ii) · 7 marks · AO1, 2
(ii) Complete the flowchart below for the synthesis of two compounds starting from prenal. O NaBH4 prenal reagent(s): ......................... reagent(s): .............................. catalyst: .............................. reagent(s): ......................... reagent(s): ......................... catalyst: H+ catalyst: H+ O O O O [7]
21. November 2021 · Paper 2 · Q19(b) · 6 marks · AO2, 3
(b)* A student intends to synthesise compound A using the two-stage route below. O Stage 1 Stage 2 CH2 Cl Intermediate CH2 C OH (chloromethyl)benzene Compound A Plan a two-stage synthesis to prepare 5.44 g of compound A starting from (chloromethyl)benzene, C6H5CH2Cl . Assume that the overall percentage yield of compound A from (chloromethyl)benzene is 25%. In your answer, include the mass of C6H5CH2Cl required, reagents, and equations where appropriate. Purification details are not required. [6] ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... Additional answer space if required. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ...................................................................................................................................................
22. November 2021 · Paper 2 · Q20(a)(iii) · 3 marks · AO2, 3
(iii) Two molecules of salicylic acid can react together in the presence of an acid catalyst to form compound B. Compound B has three rings and a molecular formula of C14H8O4. Write the equation for this reaction showing the structures of organic compounds. [3]
23. November 2021 · Paper 2 · Q20(b)(i) · 3 marks · AO3
(b) A student reacts phenol with nitric acid and sulfuric acid at 100 °C to form impure crystals of an organic compound, C. The student purifies the crystals by recrystallisation. (i) Describe how the student could recrystallise the impure crystals to obtain a pure sample of C. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [3]
24. November 2021 · Paper 3 · Q5(b)(iii) · 3 marks · AO2, 3
(iii) In the Schmidt reaction, hydrazoic acid, HN3, reacts with carboxylic acids to form primary amines. For example, HN3 reacts with RCOOH to form RNH2 and two gases that are found in the atmosphere. Write the equation for the reaction of HN3 with 2-methylbutanoic acid. Show structures for organic compounds. [3]
25. November 2020 · Paper 2 · Q3 · 1 marks · AO1
3 Which of these reagent(s) will not react with HOCH2CH2CH2COOH? A NaCN in ethanol B C2H5OH in the presence of an acid catalyst C (CH3CO)2O D concentrated H2SO4 Your answer [1]
26. November 2020 · Paper 2 · Q17(c)(ii) · 5 marks · AO3
(ii) The chemist develops a three-stage synthesis of compound D from compound C. Complete the flowchart. Show structures for organic compounds. reagent: ...................................... catalyst: ...................................... compound C 1. Sn + HCl 2. Neutralise O HN reagent: ...................................... compound D [5]
27. November 2020 · Paper 2 · Q21(a) · 5 marks · AO2
21 This question is about organic compounds containing nitrogen. (a) Salt H, (CH3)2CHNH3Cl , is used in the manufacture of garden weedkillers. The flowchart shows the synthesis of the salt H from propanone. Complete the flowchart. Show structures for organic compounds. propanone NaBH4 reagent: ...................................... Br CH H3C CH3 reagent: ...................................... NH3Cl reagent: ...................................... CH H3C CH3 salt H [5]
28. November 2020 · Paper 2 · Q21(b)(i) · 3 marks · AO1
(b) Aspartame, shown below, is an artificial sweetener commonly used as a sugar substitute. O NH2 O H N O OH O aspartame (i) Aspartame contains several functional groups. Apart from the benzene ring, name the functional groups in aspartame. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [3]
29. November 2020 · Paper 2 · Q21(b)(ii) · 4 marks · AO2
(ii) A sample of aspartame is hydrolysed with aqueous acid. Draw the structures of the three organic products of the complete acid hydrolysis of aspartame. [4]
30. November 2020 · Paper 3 · Q1(a)(i) · 2 marks · AO1
1 This question is about organic chemistry. (a) This part is about two practical techniques used in organic preparations. (i) Complete the missing labels on the diagram and name the technique. ......................................... ...................................................... ......................................... ...................................................... Heat Name of technique: ...................................................................................................... [2]
31. November 2020 · Paper 3 · Q1(a)(ii) · 2 marks · AO2
(ii) Draw a labelled diagram to show apparatus set up for filtration under reduced pressure (vacuum filtration). [2]
32. November 2020 · Paper 3 · Q1(c) · 2 marks · AO3
(c) The amino acid Z−H2NCH=CHCOOH can react to form a cyclic compound with the molecular formula C3H3NO and one other product. Complete the equation for this reaction. H2N COOH C C + H H [2]
33. June 2019 · Paper 2 · Q6 · 1 marks · AO2
6 What is the organic product of the reaction below? CH2Cl KOH(aq) Cl CH2OH A Cl CH2Cl B OH CH2OH C OH HO CH2Cl D Cl Your answer [1]
34. June 2019 · Paper 2 · Q15 · 1 marks · AO1
15 The structure of a compound used to treat influenza is shown below. O O O HN NH2 O Which functional group(s) is/are in a molecule of the compound? 1 Ester 2 Secondary amide 3 Ketone A 1, 2 and 3 B Only 1 and 2 C Only 2 and 3 D Only 1 Your answer [1]
35. June 2019 · Paper 2 · Q17(a)(i) · 4 marks · AO2
17 This question is about α-amino acids, RCH(NH2)COOH. (a) Table 17.1 shows the R groups in four amino acids. Amino acid R group alanine (ala) CH3– serine (ser) HOCH2– leucine (leu) (CH3)2CHCH2– glycine (gly) H– Table 17.1 (i) In the boxes, draw the organic products for the reactions of serine shown below. (CH3)2CHOH / H2SO4 H+(aq) H O excess CH3COCl H2N C C OH CH2 OH serine [4]
36. June 2019 · Paper 2 · Q18(a)(ii) · 5 marks · AO2
(ii) In the boxes, draw the organic products for the reactions of the functional groups in ester A shown below. Each reaction forms two organic products. + H+(aq) O Br O Ester A excess OH–(aq) + [5]
37. June 2019 · Paper 2 · Q18(e)(i) · 6 marks · AO3
(e)* A student intends to synthesise ester C. H O H3C C C O CH3 CH3 Ester C (i) Plan a two-stage synthesis to prepare 12.75 g of ester C starting from 2-methylpropanal, (CH3)2CHCHO. Assume the overall percentage yield of ester C from 2-methylpropanal is 40%. In your answer include the mass of 2-methylpropanal required, reagents, conditions and equations where appropriate. Purification details are not required. [6] ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... Additional answer space if required ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...........................................................................................................................................
38. June 2019 · Paper 2 · Q19(b)(iv) · 7 marks · AO2
(iv) Complete the flowchart for the synthesis of compounds D and E from phenylethanone. H3C O C NaBH4 phenylethanone NaCN(aq) / H+(aq) .................................................. H H C H C .................................................. CH3 compound D Br C CN .................................................. CH3 H2N C COOH .................................... compound E [7]
39. June 2019 · Paper 3 · Q2(e) · 2 marks · AO3
(e) In Step 3, describe how the student can recrystallise the impure crystals to obtain pure benzoic acid. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................. [2]
40. June 2019 · Paper 3 · Q4(b)(iii) · 4 marks · AO3
(iii) α-Terpineol contains two functional groups. For each functional group, choose a reagent that reacts with that group only. Draw the structures for the organic products of the reactions. Show structures for organic compounds. Reagent(s) ................................................................................................................................ Name of functional group that reacts ........................................................................................ Structure of organic product Reagent(s) ................................................................................................................................ Name of functional group that reacts ........................................................................................ Structure of organic product [4]
41. June 2018 · Paper 2 · Q14 · 1 marks ·
14 A solid organic compound can be purified by recrystallisation. Which statement(s) about recrystallisation is/are true? 1 The organic compound is more soluble in hot solvent. 2 The hot solution is cooled before the purified organic compound is collected. 3 The melting point of the purified organic compound is lower than the impure compound. A 1, 2 and 3 B Only 1 and 2 C Only 2 and 3 D Only 1 Your answer [1]
42. June 2018 · Paper 2 · Q16(c) · 3 marks ·
(c) The flowchart below shows some reactions of compound C. In the boxes, draw the organic products of these reactions. excess CH3OH/H2SO4 Steam COOH HOOC H3PO4 compound C polymerisation repeat unit of polymer [3]
43. June 2018 · Paper 2 · Q21(a) · 3 marks ·
21 This question is about aromatic carboxylic acids and their derivatives. (a) The flowchart below shows some reactions of compound H. In the boxes, draw the organic products of these reactions. Na2CO3(aq) NaOH(aq) O C OH HO compound H Br2 [3]
44. June 2018 · Paper 2 · Q22(c)(ii) · 2 marks ·
(ii) Solketal has been investigated as a potential fuel additive. HO O O solketal Solketal is synthesised from propane-1,2,3-triol and a carbonyl compound. Construct a balanced equation for this synthesis. Show structures for the organic compounds in your equation. [2]
45. June 2018 · Paper 3 · Q4(b)(i) · 2 marks ·
(b) Paracetamol is a solid organic compound used in tablets as a painkiller. H HO N C CH3 paracetamol O (i) Name the functional groups present in paracetamol. ...................................................................... ...................................................................... [2]
46. June 2018 · Paper 3 · Q4(b)(ii) · 6 marks ·
(ii)* A chemist prepares a pure solid sample of paracetamol from 4-nitrophenol in two stages: H Stage 1 Stage 2 HO NO2 Intermediate HO N CH3COCl C CH3 4-nitrophenol paracetamol O Describe a two-stage synthesis of 5.00 g of pure paracetamol from 4-nitrophenol. The overall percentage yield of paracetamol from 4-nitrophenol is 40.0%. In your answer, include the mass of 4-nitrophenol required, the reagents and intermediate, and details of the purification of paracetamol. [6] ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... Additional answer space if required. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...........................................................................................................................................
47. June 2018 · Paper 3 · Q6(a)(iv) · 1 marks ·
(iv) A similar reaction takes place when propanone, (CH3)2CO, is mixed with OH–(aq) ions. Draw the structure of the organic product of this reaction. [1]
48. June 2017 · Paper 2 · Q7 · 1 marks ·
7 Which molecule is a secondary amine? NH N O O NH N O O A B C D Your answer [1]
49. June 2017 · Paper 2 · Q17(a)(ii) · 6 marks ·
(ii)* A chemist carries out the reaction in Equation 17.1 using 4.97 g of benzoic acid. The chemist obtains 3-nitrobenzoic acid as an impure solid. The chemist purifies the solid to obtain 4.85 g of 3-nitrobenzoic acid. Describe a method to obtain a pure sample of 3-nitrobenzoic acid from the impure solid, determine the percentage yield and check its purity. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [6]
50. June 2017 · Paper 2 · Q17(c)(i) · 3 marks ·
(c) A student synthesises 3-bromophenylamine, shown below, starting from nitrobenzene. (i) Complete the flowchart showing the structure of the intermediate and the formulae of the reagents for each stage. NO2 bromination reagents: ............................................. reduction NH2 reagents: ............................................. Br 3-bromophenylamine intermediate [3]
51. June 2017 · Paper 2 · Q18(a)(ii) · 3 marks ·
(ii) Compound G is used to synthesise compounds H and I as shown in the flowchart below. Complete the flowchart showing the structure of compound G and the formulae of the reagents for Reaction 2 and Reaction 3. OH O H C C OH H compound I Reaction 3 reagents: .......................................... OH Reaction 1 H C CN NaCN/H+ H compound G Reaction 2 reagents: .......................................... OH H H C C NH2 H H compound H [3]
52. June 2017 · Paper 2 · Q19(c)(i) · 5 marks ·
(c) Alcohols are important in organic synthesis and can be formed by the reduction of carbonyl compounds. (i) Complete the flowchart by filling in each box. carbonyl compound reduction reagent(s): .......................................... OH NaBr / H2SO4 compound K acid catalyst heat + structural isomers [5]
53. June 2017 · Paper 3 · Q4(b)(ii) · 3 marks ·
(ii) Compound A is heated with a few drops of concentrated sulfuric acid as a catalyst. A cyclic ‘dimer’ of compound A forms. Equation Type of reaction ........................................................................................................... [3]
54. June 2017 · Paper 3 · Q5(a)(ii) · 2 marks ·
(ii) Thiols react with carboxylic acids to form thioesters. Write an equation for the reaction of butane-1-thiol with ethanoic acid. Use structures for all organic compounds with the functional groups clearly displayed. [2]
55. June 2017 · Paper 3 · Q5(a)(iv) · 2 marks ·
(iv) Propane-1,3-dithiol reacts with carbonyl compounds in a condensation reaction to form a cyclic organic sulfur product. Write an equation for the reaction of propane-1,3-dithiol with propanone. Use structures for organic compounds. [2]
56. June 2017 · Paper 3 · Q5(b) · 6 marks ·
(b)* The structures for six naturally occurring organic compounds with pleasant smells, B–G, are shown below. The common names in brackets relate to their source and smell. OH O B C (linalool) (citral) O OH D (geraniol) E (camphor) O OH F G (menthol) (ionone) Explain how chemical tests would allow each compound to be distinguished from the other compounds. In your answer, include essential details for all test procedures and observations. Details of apparatus and quantities are not required. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [6]

Mark schemes

1. June 2025 · Paper 2 · Q14
Mark scheme June 2025 Paper 2 Q14
2. June 2025 · Paper 2 · Q22(b)(i)
Mark scheme June 2025 Paper 2 Q22(b)(i)
3. June 2025 · Paper 2 · Q22(b)(ii)
Mark scheme June 2025 Paper 2 Q22(b)(ii)
4. June 2025 · Paper 3 · Q5(a)(iv)
Mark scheme June 2025 Paper 3 Q5(a)(iv)
5. June 2024 · Paper 2 · Q20(d)
Mark scheme June 2024 Paper 2 Q20(d)
6. June 2024 · Paper 2 · Q23(a)
Mark scheme June 2024 Paper 2 Q23(a)
7. June 2023 · Paper 2 · Q4
Mark scheme June 2023 Paper 2 Q4
8. June 2023 · Paper 2 · Q18(c)
Mark scheme June 2023 Paper 2 Q18(c)
9. June 2023 · Paper 2 · Q19
Mark scheme June 2023 Paper 2 Q19
10. June 2023 · Paper 2 · Q22(b)
Mark scheme June 2023 Paper 2 Q22(b)
11. June 2023 · Paper 3 · Q3
Mark scheme June 2023 Paper 3 Q3
12. June 2023 · Paper 3 · Q5(b)(ii)
Mark scheme June 2023 Paper 3 Q5(b)(ii)
13. June 2022 · Paper 2 · Q4
Mark scheme June 2022 Paper 2 Q4
14. June 2022 · Paper 2 · Q16(c)(i)
Mark scheme June 2022 Paper 2 Q16(c)(i)
15. June 2022 · Paper 2 · Q19(b)
Mark scheme June 2022 Paper 2 Q19(b)
16. June 2022 · Paper 2 · Q19(e)
Mark scheme June 2022 Paper 2 Q19(e)
17. June 2022 · Paper 2 · Q20(e)
Mark scheme June 2022 Paper 2 Q20(e)
18. November 2021 · Paper 2 · Q16(d)(ii)
Mark scheme November 2021 Paper 2 Q16(d)(ii)
19. November 2021 · Paper 2 · Q18(b)
Mark scheme November 2021 Paper 2 Q18(b)
20. November 2021 · Paper 2 · Q19(a)(ii)
Mark scheme November 2021 Paper 2 Q19(a)(ii)
21. November 2021 · Paper 2 · Q19(b)
Mark scheme November 2021 Paper 2 Q19(b)
22. November 2021 · Paper 2 · Q20(a)(iii)
Mark scheme November 2021 Paper 2 Q20(a)(iii)
23. November 2021 · Paper 2 · Q20(b)(i)
Mark scheme November 2021 Paper 2 Q20(b)(i)
24. November 2021 · Paper 3 · Q5(b)(iii)
Mark scheme November 2021 Paper 3 Q5(b)(iii)
25. November 2020 · Paper 2 · Q3
Mark scheme November 2020 Paper 2 Q3
26. November 2020 · Paper 2 · Q17(c)(ii)
Mark scheme November 2020 Paper 2 Q17(c)(ii)
27. November 2020 · Paper 2 · Q21(a)
Mark scheme November 2020 Paper 2 Q21(a)
28. November 2020 · Paper 2 · Q21(b)(i)
Mark scheme November 2020 Paper 2 Q21(b)(i)
29. November 2020 · Paper 2 · Q21(b)(ii)
Mark scheme November 2020 Paper 2 Q21(b)(ii)
30. November 2020 · Paper 3 · Q1(a)(i)
Mark scheme November 2020 Paper 3 Q1(a)(i)
31. November 2020 · Paper 3 · Q1(a)(ii)
Mark scheme November 2020 Paper 3 Q1(a)(ii)
32. November 2020 · Paper 3 · Q1(c)
Mark scheme November 2020 Paper 3 Q1(c)
33. June 2019 · Paper 2 · Q6
Mark scheme June 2019 Paper 2 Q6
34. June 2019 · Paper 2 · Q15
Mark scheme June 2019 Paper 2 Q15
35. June 2019 · Paper 2 · Q17(a)(i)
Mark scheme June 2019 Paper 2 Q17(a)(i)
36. June 2019 · Paper 2 · Q18(a)(ii)
Mark scheme June 2019 Paper 2 Q18(a)(ii)
37. June 2019 · Paper 2 · Q18(e)(i)
Mark scheme June 2019 Paper 2 Q18(e)(i)
38. June 2019 · Paper 2 · Q19(b)(iv)
Mark scheme June 2019 Paper 2 Q19(b)(iv)
39. June 2019 · Paper 3 · Q2(e)
Mark scheme June 2019 Paper 3 Q2(e)
40. June 2019 · Paper 3 · Q4(b)(iii)
Mark scheme June 2019 Paper 3 Q4(b)(iii)
41. June 2018 · Paper 2 · Q14
Mark scheme June 2018 Paper 2 Q14
42. June 2018 · Paper 2 · Q16(c)
Mark scheme June 2018 Paper 2 Q16(c)
43. June 2018 · Paper 2 · Q21(a)
Mark scheme June 2018 Paper 2 Q21(a)
44. June 2018 · Paper 2 · Q22(c)(ii)
Mark scheme June 2018 Paper 2 Q22(c)(ii)
45. June 2018 · Paper 3 · Q4(b)(i)
Mark scheme June 2018 Paper 3 Q4(b)(i)
46. June 2018 · Paper 3 · Q4(b)(ii)
Mark scheme June 2018 Paper 3 Q4(b)(ii)
47. June 2018 · Paper 3 · Q6(a)(iv)
Mark scheme June 2018 Paper 3 Q6(a)(iv)
48. June 2017 · Paper 2 · Q7
Mark scheme June 2017 Paper 2 Q7
49. June 2017 · Paper 2 · Q17(a)(ii)
Mark scheme June 2017 Paper 2 Q17(a)(ii)
50. June 2017 · Paper 2 · Q17(c)(i)
Mark scheme June 2017 Paper 2 Q17(c)(i)
51. June 2017 · Paper 2 · Q18(a)(ii)
Mark scheme June 2017 Paper 2 Q18(a)(ii)
52. June 2017 · Paper 2 · Q19(c)(i)
Mark scheme June 2017 Paper 2 Q19(c)(i)
53. June 2017 · Paper 3 · Q4(b)(ii)
Mark scheme June 2017 Paper 3 Q4(b)(ii)
54. June 2017 · Paper 3 · Q5(a)(ii)
Mark scheme June 2017 Paper 3 Q5(a)(ii)
55. June 2017 · Paper 3 · Q5(a)(iv)
Mark scheme June 2017 Paper 3 Q5(a)(iv)
56. June 2017 · Paper 3 · Q5(b)
Mark scheme June 2017 Paper 3 Q5(b)