Hydrocarbons: past paper questions

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• Question 28May/June 2026, paper 11Multiple choice1 mark

  This question is about the conversion of but-2-ene to butanone. What are the correct steps to carry out this conversion?

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• Question 27Oct/Nov 2025, paper 11Multiple choice1 mark

  Which intermediate ion forms in the greatest amount during the addition of $\text{HBr}$ to propene?

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• Question 25Oct/Nov 2024, paper 11Multiple choice1 mark

  Ethene reacts with steam in the presence of sulfuric acid. $${\text{C}}_2{\text{H}}_4+{\text{H}}_2\text{O}\to {\text{CH}}_3{\text{CH}}_2\text{OH}$$ Which type of reaction is this?

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• Question 28Oct/Nov 2023, paper 11Multiple choice1 mark

  The hydrocarbon ${\mathrm{C}}_{17}{\mathrm{H}}_{36}$ can be cracked. Which compound is the least likely to be produced in this reaction?

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• Question 29May/June 2026, paper 11Multiple choice1 mark

  Which compound will decolourise ${\text{Br}}_2\text{(aq)}$ in the dark?

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• Question 28Oct/Nov 2025, paper 11Multiple choice1 markHas a diagram

  Two hydrocarbons, ${\text{R–CH}}_3$ and ${\text{R’–CH}}_3$, react separately with bromine in the presence of ultraviolet light. One of these hydrocarbons is unsaturated. In each case, free radical substitution reactions occur.

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• Question 29Oct/Nov 2024, paper 11Multiple choice1 markHas a diagram

  Vitamin A contains retinol. Under appropriate conditions, acidified ${\text{KMnO}}_4(\text{aq})$ can be used to break $\text{C=C}$ bonds. After these bonds have been broken, further oxidation of the fragments may occur.

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• Question 29Oct/Nov 2023, paper 11Multiple choice1 markHas a diagram

  Which compound has an $M_r$ of 84 and will react with $\mathrm{H}\mathrm{B}\mathrm{r}$ to give a product with an $M_r$ of 164.9?

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• Question 30May/June 2026, paper 11Multiple choice1 markHas a diagram

  The structure of compound Z is shown. One mole of compound Z reacts completely with two moles of hydrogen bromide. What is the structure of the major product of this reaction?

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• Question 29Oct/Nov 2025, paper 11Multiple choice1 mark

  The fumes from the exhausts of petrol-burning cars contain the following pollutants. 1 unburnt hydrocarbons 2 nitrogen dioxide 3 carbon monoxide Which pollutants are removed by oxidation in a catalytic converter?

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• Question 30Oct/Nov 2024, paper 11Multiple choice1 markHas a diagram

  The structure of limonene is shown. What are the number of moles of carbon dioxide and water produced when a sample of limonene is completely combusted in oxygen?

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• Question 30Oct/Nov 2023, paper 11Multiple choice1 markHas a diagram

  $\beta$-carotene is responsible for the orange colour of carrots. $\beta$-carotene is oxidised by hot, concentrated, acidified ${\mathrm{K}\mathrm{M}\mathrm{n}\mathrm{O}}_4$. When an individual molecule of $\beta$-carotene is oxidised in this way, many product molecules are formed.

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• Question 25May/June 2026, paper 12Multiple choice1 mark

  What is the least number of carbon atoms in a non-cyclic alkane molecule that has a chiral centre?

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• Question 31Oct/Nov 2025, paper 11Multiple choice1 mark

  1,4-dibromobutane reacts with an excess of ethanolic sodium hydroxide until no further reaction takes place. What is the relative formula mass of the major organic product?

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• Question 31Oct/Nov 2024, paper 11Multiple choice1 mark

  The reaction of chlorine with methane is carried out in the presence of light. What is the function of the light?

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• Question 30Oct/Nov 2023, paper 12Multiple choice1 markHas a diagram

  The structure of compound X is shown. One mole of compound X reacts completely with two moles of hydrogen bromide. What is the structure of the major product of this reaction?

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• Question 26May/June 2026, paper 12Multiple choice1 mark

  The first propagation step in the reaction between methane and chlorine is shown. $${\text{CH}}_4+{\text{Cl}}^{\bullet }\to {\text{CH}}_3^{\bullet }+\text{HCl}$$ How many different first propagation steps are possible in the reaction between pentane and chlorine?

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• Question 27Oct/Nov 2025, paper 12Multiple choice1 mark

  What is the major product when 2-methylpent-2-ene reacts with hydrogen bromide?

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• Question 38Oct/Nov 2024, paper 12Multiple choice1 mark

  Which statement about ${\mathrm{H}}_2{\mathrm{C}=\mathrm{C}(\mathrm{C}\mathrm{H}}_3){\mathrm{C}\mathrm{H}}_2{\mathrm{C}\mathrm{O}}_2{\mathrm{C}\mathrm{H}}_3$ is correct?

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• Question 31Oct/Nov 2023, paper 12Multiple choice1 markHas a diagram

  The formulae of three compounds are shown. $${\text{C}}_3{\text{H}}_7\text{CHO}{\text{C}}_2{\text{H}}_5{\text{COCH}}_3{\text{CH}}_2{\text{CHCH}}_2{\text{CH}}_2\text{OH}$$ Only one of these compounds will decolourise bromine water.

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• Question 28May/June 2026, paper 12Multiple choice1 mark

  Hydrogen iodide undergoes an addition reaction with propene forming 2-iodopropane. When propene is bubbled through iodine monochloride, $\text{ICl}$, dissolved in a suitable solvent, a similar reaction occurs. Which product will be present in the greatest yield?

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• Question 28Oct/Nov 2025, paper 12Multiple choice1 mark

  Pent-2-ene is reacted with cold, dilute, acidified manganate(VII) ions. What is the major product?

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• Question 32Oct/Nov 2023, paper 12Multiple choice1 mark

  Which list contains a compound that is not made during the free radical substitution of methane with chlorine?

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• Question 32May/June 2026, paper 12Multiple choice1 mark

  Methylpropene reacts with steam in the presence of an ${\text{H}}_3{\text{PO}}_4$ catalyst. The major product of this reaction is then heated with an excess of acidified ${\text{KMnO}}_4$. If the mixture is distilled after heating, which organic compound will be collected?

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• Question 29Oct/Nov 2025, paper 12Multiple choice1 markHas a diagram

  Limonene is an oil formed in the peel of citrus fruits. Which product is formed when an excess of bromine, ${\text{Br}}_2(\text{l})$, reacts with limonene at room temperature in the dark?

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• Question 29Oct/Nov 2024, paper 13Multiple choice1 markHas a diagram

  Vitamin A contains retinol. [Diagram of retinol] Under appropriate conditions, acidified ${\mathrm{K}\mathrm{M}\mathrm{n}\mathrm{O}}_4(\mathrm{a}\mathrm{q})$ can be used to break $\mathrm{C}=\mathrm{C}$ bonds. After these bonds have been broken, further oxidation of the fragments may occur.

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• Question 39May/June 2026, paper 12Multiple choice1 mark

  Structural isomerism and stereoisomerism should be considered when answering this question.

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• Question 30Oct/Nov 2024, paper 13Multiple choice1 markHas a diagram

  The structure of limonene is shown. [Diagram of limonene] What are the number of moles of carbon dioxide and water produced when a sample of limonene is completely combusted in oxygen?

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• Question 27May/June 2026, paper 13Multiple choice1 mark

  Alkenes react with hydrogen bromide. The reaction proceeds via an intermediate carbocation. The more stable the intermediate, the faster the reaction.

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• Question 28May/June 2026, paper 13Multiple choice1 mark

  Ethane reacts with bromine by a free-radical substitution mechanism. The mechanism for this reaction has three steps: initiation, propagation and termination. Which species is a possible product in one of the steps?

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