Reactions of alkenes: Edexcel International A Level Chemistry questions

Every Edexcel International A Level Chemistry exam question on Reactions of alkenes (specification points 5.4–5.6), 2019–2025, with its mark scheme and examiner’s report.

All 96 questions on Reactions of alkenes, as a list

June 2025, AS Unit 1, Q19 (1 mark): Which is the correct mechanism for the electrophilic addition reaction between HBr and pent-1-ene to give the major product? H A CH2 CHCH2CH2CH3 CH3 CCH2CH2CH3
June 2025, Unit 5, Q20(a)(iv) (2 marks): In Step Y a diol is formed as an intermediate before further oxidation. The mixture is heated so the reaction can proceed. Suggest the reagents required to form
June 2025, Unit 5, Q20(a)(v) (1 mark): Suggest a reason why it is unlikely the reaction scheme proceeds by this route in plants. (1)
January 2025, AS Unit 1, Q17 (1 mark): Bromine and bromine water can be used to test for a carbon‑carbon double bond. When bromine water reacts with 2‑methylbut‑2‑ene, there is one major organic prod
January 2025, AS Unit 1, Q24(b) (1 mark): A few drops of a purple solution of acidified potassium manganate(VII) were added to a sample of liquid X and shaken. The solution remained purple. State what c
January 2025, AS Unit 1, Q25(b)(ii) (2 marks): Explain why chlorine reacts with alkenes even though it is not a polar molecule. (2)
October 2024, AS Unit 1, Q19(a)(i) (1 mark): Name the mechanism and type of reaction for Reaction 1. (1)
October 2024, AS Unit 1, Q19(a)(ii) (3 marks): Explain why the structures of the intermediates in Reaction 1 mean that 2‑chloropropane is formed in greater yield than 1‑chloropropane. (3)
October 2024, AS Unit 1, Q19(b) (4 marks): Reaction 2 proceeds in two stages. The equation for the first stage is shown. CH2 + H2SO4 → CH3CH(OSO2OH)CH3 CH3CH The mechanism for this reaction is the same a
October 2024, AS Unit 3, Q3(b)(i) (1 mark): The purified product was treated with a small volume of bromine water and shaken. The bromine water was not decolourised. State the most likely conclusion that
June 2024, AS Unit 1, Q3(b) (1 mark): Limonene is completely hydrogenated by hydrogen in the presence of a nickel catalyst. What is the empirical formula of the product formed? (1) A C5H11 B C5H9 C
June 2024, AS Unit 1, Q19(b)(i) (1 mark): The degree of unsaturation can be determined by the reaction with bromine water. Name the type of reaction. (1) Data using 0.5 g of some unsaturated fat in this
June 2024, AS Unit 1, Q19(b)(ii) (3 marks): Plot a graph of the data. Include a line of best fit. (3)
June 2024, AS Unit 1, Q19(b)(iii) (1 mark): Data for the bromination of 0.5 g samples of a margarine are shown. Volume of 0.0625 mol dm–3 Trial bromine water / cm3 1 36.9 2 34.1 3 39.3 4 32.5 Calculate th
June 2024, AS Unit 1, Q19(b)(iv) (1 mark): Determine the average number of C C bonds per molecule of the unknown sample to 2 significant figures, using your graph. (1)
June 2024, AS Unit 1, Q19(c)(i) (4 marks): Using the simplest alkene as an example, draw the mechanism to show the reaction with liquid bromine. (4)
June 2024, AS Unit 2, Q19(a) (1 mark): The hydration of ethene requires a catalyst which is coated onto a solid silicon dioxide support. Identify, by name or formula, the catalyst used. (1)
June 2024, AS Unit 2, Q20(b)(ii) (1 mark): Both myrcene and limonene can be completely hydrogenated by reaction with hydrogen. State the conditions required for hydrogenation of alkenes. (1)
June 2024, AS Unit 2, Q20(b)(iv) (1 mark): Give the IUPAC name of the product formed by complete hydrogenation of myrcene. (1)
June 2024 (R), AS Unit 3, Q3(e)(i) (2 marks): Describe a laboratory test that could be used to distinguish between solutions of these acids. (2)
January 2024, AS Unit 1, Q19(c)(i) (4 marks): Give the mechanism for this reaction. Include curly arrows and relevant dipoles and lone pairs. (4)
January 2024, AS Unit 1, Q19(c)(ii) (2 marks): Explain why only a small amount of 1‑chloropropane is produced in this reaction. (2)
January 2024, AS Unit 3, Q1(b) (4 marks): Describe a chemical test and the expected positive result for both functional group 2 and functional group 3. (4) Functional group 2 Test Result Functional grou
October 2023, AS Unit 1, Q10(a) (1 mark): Which of these steps is most likely to occur in the reaction? H H H (1) A H C C C+ :Cl– H H H H H H B H C C C+ :Cl– H H H :Cl– H H + C H C C C H H H H :Cl– H H
October 2023, AS Unit 1, Q10(b) (1 mark): The reaction of propene with hydrogen chloride is an example of (1) A free radical substitution B free radical addition C electrophilic substitution D electroph
October 2023, AS Unit 1, Q11 (1 mark): Ethene reacts with acidified potassium manganate(VII). A student makes four statements about the reaction. • the organic product can show geometric isomerism •
October 2023, AS Unit 1, Q20(c)(iii) (1 mark): Deduce the number of carbon-carbon double bonds in a molecule of α-bisabolene, using your answers to (c)(i) and (c)(ii). (1)
October 2023, AS Unit 2, Q21(a)(iii) (2 marks): Reagents were added to separate samples of X to identify the functional groups in the molecule. Complete Table 1. (2) Table 1 Reagent Observation Functional gro
October 2023, AS Unit 2, Q21(c)(i) (2 marks): Suggest suitable reagents and conditions for the conversion of propene to propane‑1,2‑diol. (2)
October 2023, AS Unit 3, Q3(h) (2 marks): Separate samples of cyclohexanol and the cyclohexene product were tested with phosphorus(V) chloride and with bromine water. Complete the table to show the obse
June 2023, AS Unit 3, Q3(b)(ii) (2 marks): Give a chemical test, including the expected result, to confirm the presence of the C C double bond in but‑1‑ene. (2)
January 2023, AS Unit 1, Q22(a)(i) (1 mark): Identify, by name or formula, the catalyst needed for Reaction 1. . (1)
January 2023, AS Unit 1, Q22(a)(ii) (1 mark): Name product A. (1)
January 2023, AS Unit 1, Q22(a)(iii) (2 marks): Identify, by name or formula, the substances needed for Reaction 2. (2)
January 2023, AS Unit 1, Q22(a)(iv) (1 mark): Draw the displayed formula of product B. (1)
January 2023, AS Unit 1, Q22(c)(i) (4 marks): Complete the mechanism to show this reaction. Include curly arrows, and any relevant lone pairs and dipoles. (4) H Br H C C C H H H H Br
January 2023, AS Unit 1, Q22(c)(ii) (2 marks): Explain why 1,2‑dibromopropane is the major product instead of 1,3‑dibromopropane. (2)
January 2023, AS Unit 3, Q1(a) (2 marks): P has the molecular formula C6H12. P is a straight‑chain molecule that contains one functional group. Bromine water is decolourised when shaken with P. Identify
October 2022, AS Unit 1, Q15(c)(i) (4 marks): Draw the mechanism for the formation of the major product of the reaction between 2‑methylpropene and hydrogen bromide, HBr. Include curly arrows, and relevant
October 2022, AS Unit 1, Q15(c)(ii) (1 mark): Give the reason why your product in (c)(i) is the major product. (1)
October 2022, AS Unit 1, Q17(b)(i) (1 mark): A few drops of acidified potassium manganate(VII) solution are mixed with a sample of limonene. State the colour change. (1) From to
October 2022, AS Unit 1, Q17(b)(ii) (1 mark): Draw the skeletal formula of the structure of the organic product formed when the reaction in (b)(i) is carried out with excess acidified potassium manganate(VI
October 2022, AS Unit 1, Q17(b)(iii) (1 mark): Name the type of reaction that limonene undergoes in (b)(i). . (1)
October 2022, AS Unit 2, Q23(d)(i) (2 marks): For Reaction 1, give the name or formula of a suitable reagent, stating the conditions for the reaction. (2) Reagent Conditions
October 2022, AS Unit 2, Q23(d)(ii) (2 marks): For Reaction 2, give the name or formula of a suitable reagent, stating the type of reaction taking place. (2) Reagent Type of reaction
October 2022, AS Unit 2, Q23(d)(iii) (2 marks): For Reaction 3, give the name or formula of a suitable reagent, writing an equation for the reaction taking place. (2) Reagent Equation
June 2022, AS Unit 1, Q15 (1 mark): A hydrocarbon X has a molar mass of 98 g mol−1 . When a sample of X is shaken with bromine water, the colour of the bromine water does not change. Which of thes
June 2022, AS Unit 1, Q22(c)(i) (1 mark): Name the type and mechanism of the reaction. (1)
June 2022, AS Unit 1, Q22(c)(ii) (4 marks): The diagram shows a simplified structure of zingiberene, in which part of the molecule is represented by A. Complete the mechanism for the reaction of zingibere
June 2022, AS Unit 1, Q22(c)(iii) (2 marks): For the reaction in (c)(ii) there are two possible products: A Br A Br I II Explain why I is the major product, by referring to your mechanism. (2)
June 2022, AS Unit 1, Q22(d)(i) (1 mark): Identify the catalyst, by name or formula. (1)
June 2022, AS Unit 1, Q22(d)(ii) (4 marks): 2.0 mol of zingiberene react completely with hydrogen at 150 °C and a pressure of 120 kPa. Calculate the minimum volume of hydrogen needed under these condition
June 2022, AS Unit 3, Q3(g)(i) (2 marks): State a chemical test and the expected observation for a C C double bond. (2)
June 2022, Unit 6, Q4(c)(i) (1 mark): Give the colour change for this reaction. (1)
June 2022, Unit 6, Q4(c)(ii) (1 mark): Draw the structure of the organic product which might be expected when excess acidified potassium manganate(VII) reacts with limonene. (1)
January 2022, AS Unit 1, Q21(b)(i) (3 marks): In each box, draw the structure of the organic product of the reaction. (3)
January 2022, AS Unit 1, Q21(b)(ii) (3 marks): Propene also reacts with hydrogen bromide, HBr. Give the mechanism for this reaction to form the major product. Include curly arrows, and relevant lone pairs an
January 2022, AS Unit 1, Q21(c)(iv) (3 marks): In an experiment, 0.050 mol of alpha-ocimene reacted with 3.6 dm3 of hydrogen, H2 , in the presence of a catalyst. Deduce the structure of the product of this r
October 2021, AS Unit 1, Q15(b)(iii) (4 marks): Some reactions of but-1-ene are shown. Product 1 Cl2 steam / H+ H2 / Ni Product 4 Product 2 CH3CH2CH CH2 KMnO4 / H+ Product 3 Give the name and structural formu
October 2021, AS Unit 3, Q2(a) (4 marks): Geraniol has two different types of functional group. Name the functional groups, giving a chemical test and its positive result to show the presence of each gr
October 2021, AS Unit 3, Q2(e) (1 mark): State the appearance of the flame when geraniol is ignited. (1)
October 2021, AS Unit 3, Q2(f)(i) (1 mark): State the essential condition required for this reaction. (1)
October 2021, AS Unit 3, Q2(f)(ii) (1 mark): Draw the skeletal formula of the product of this reaction. (1) OH geraniol
June 2021, AS Unit 1, Q23(c)(i) (1 mark): Draw the skeletal formula of compound X formed in Reaction 1. (1)
June 2021, AS Unit 1, Q23(c)(ii) (2 marks): Give the reagent and condition needed for Reaction 2. (2) Reagent ………………………………………………………………………………………………………………………………………………… Condition …………………………………………………………………………
June 2021, AS Unit 1, Q23(d) (4 marks): Iodine monochloride, ICl, reacts with alkenes in a similar way to hydrogen bromide. Complete the mechanism for the reaction of iodine monochloride with propene
June 2021, AS Unit 1, Q23(f) (4 marks): 0.0100 mol of an alkene reacts completely with exactly 600 cm3 of hydrogen gas, measured at 298 K and 1.24 × 105 Pa pressure, to form an alkane. Use the ideal g
June 2021, AS Unit 3, Q2(b)(i) (2 marks): Give a chemical test to show the presence of the carbon-carbon double bond in Z-hex-3-en-1-ol, including the expected result. (2)
June 2021, AS Unit 3, Q2(b)(ii) (1 mark): The test you have given in (b)(i) is repeated with 1-methylcyclopentanol. Give the observation for this test with 1-methylcyclopentanol. (1)
January 2021, AS Unit 1, Q20(b) (2 marks): State one similarity and one difference that would be seen when propene is mixed with separate samples of acidified potassium manganate(VII) solution and of bro
January 2021, AS Unit 1, Q20(d)(ii) (3 marks): Draw the mechanism for the formation of 1-bromo-2-chloropropane in this reaction. Include curly arrows, and relevant lone pairs. (3)
January 2021, AS Unit 1, Q20(e) (3 marks): Propene reacts with steam in the presence of an acid catalyst to form a mixture of the alcohols propan-1-ol and propan-2-ol. Complete the mechanism for the form
January 2021, AS Unit 1, Q21(c)(i) (1 mark): Give the name of a suitable catalyst for the hydrogenation of squalene. (1)
January 2021, AS Unit 1, Q21(c)(iv) (1 mark): Write the equation, using molecular formulae, for the complete hydrogenation of squalene to squalane. State symbols are not required. (1)
January 2021, AS Unit 2, Q19(a) (6 marks): Explain the chemical reasons for the conditions used and why such a low initial yield is acceptable in the industrial process. (6)
October 2020, AS Unit 1, Q21(b)(i) (2 marks): State the colour change when an excess of cyclohexene is added to liquid bromine. (2)
October 2020, AS Unit 1, Q21(b)(ii) (4 marks): This reaction is very similar to the reaction of ethene with bromine. Draw the mechanism for this reaction of cyclohexene with bromine. Include curly arrows, an
October 2020, AS Unit 3, Q3(b) (4 marks): The organic liquid H is a pheromone thought to be involved in communication between rabbits. H O H3C CH3 State the initial and final appearance of each mixture
January 2020, AS Unit 1, Q21(c)(i) (4 marks): Draw the mechanism for the reaction between ethene and chlorine to form 1,2-dichloroethane. Include curly arrows, and relevant lone pairs and dipoles. (4)
January 2020, AS Unit 1, Q21(d)(ii) (1 mark): Compound Y reacts with water to form compound Z. Compound Z is also produced in the reaction between ethene and acidified potassium manganate(VII). Give the dis
January 2020, AS Unit 1, Q21(e) (1 mark): Ethene reacts with buta-1,3-diene to form cyclohexene as the only product. Complete the equation for the formation of cyclohexene from ethene and buta-1,3-diene
January 2020, AS Unit 1, Q21(f)(i) (1 mark): Classify the type of reaction occurring in Reaction 1. (1)
January 2020, AS Unit 1, Q21(f)(ii) (2 marks): Give the reagents and conditions needed for Reaction 2. (2)
January 2020, AS Unit 2, Q17(c) (2 marks): When dry hydrogen chloride gas reacts with 2-methylbut-2-ene, two isomeric chloroalkanes are formed. Give the structure of the major product and the reason why
January 2020, AS Unit 3, Q1(d) (2 marks): Acidified potassium manganate(VII) solution was added to separate test tubes containing samples of hexane and hexene. The test tubes were shaken gently. State w
June 2019, AS Unit 1, Q16 (1 mark): What is the name of the product when this molecule reacts with chlorine gas? A 5,5-dichloro-2-methylpentane B 4,5-dichloro-2-methylpentane C 2,3-dichloro-4-meth
June 2019, AS Unit 1, Q18 (1 mark): What reagent and conditions are used for this conversion? H H H H C C HO C C H H H H H A potassium manganate(VII) in aqueous acid B sodium hydroxide in dilute a
June 2019, AS Unit 1, Q20 (1 mark): Which is the major product of this reaction? H CH2CH3 o H Br + C C H H H H A H3C C C CH3 H Br H H B H C C CH2CH3 Br H H H C H3C C C CH2CH3 Br H H H D H3C C C CH
June 2019, AS Unit 1, Q22(c)(ii) (2 marks): Give a test for alkenes, including the positive result. (2)
June 2019, AS Unit 3, Q2(d)(i) (1 mark): State the colour change when the alkene reacts with bromine. (1)
January 2019, AS Unit 1, Q16 (1 mark): Ethene reacts with hydrogen in the presence of a heated nickel catalyst to form ethane. H H H H C C + H2 H C C H H H H H Which types of bond are broken and form
January 2019, AS Unit 1, Q23(c) (4 marks): Draw the mechanism for the reaction between 2-methylpropene and bromine, Br2. Include curly arrows, and relevant lone pairs and dipoles. Use formula 1 to repres
January 2019, AS Unit 1, Q23(d)(i) (1 mark): In Reaction 1 the reagent A is acidified potassium manganate(VII). Give the skeletal formula of organic product Q. (1)
January 2019, AS Unit 1, Q23(d)(ii) (1 mark): Give the colour change seen during Reaction 1. (1) From to
January 2019, AS Unit 1, Q23(d)(iii) (1 mark): Identify, by name or formula, reagent B in Reaction 2. (1)
January 2019, AS Unit 1, Q23(d)(iv) (2 marks): Explain why 2-bromo-2-methylpropane is the major organic product in Reaction 2. (2)

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