Infrared spectroscopy: past paper questions

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• Question 40May/June 2026, paper 11Multiple choice1 markHas a diagram

  The infrared spectrum of X shows absorptions at $2200{\text{ cm}}^{-1}$ and $1630{\text{ cm}}^{-1}$. The mass spectrum of X shows: • a peak for the molecular ion, ${\text{X}}^{+}$, with a relative abundance of 38 • a peak for the ion, $[\text{X}+1{]}^{+}$, with a relative abundance of 2.9.

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• Question 40Oct/Nov 2025, paper 12Multiple choice1 markHas a diagram

  The purity of a compound can be determined using infrared spectroscopy. The table gives the characteristic infrared absorption frequencies for some selected bonds.

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• Question 4Oct/Nov 2024, paper 21Structured11 marksHas a diagram

  Propanone, ${\text{CH}}_3{\text{COCH}}_3$, is an important organic reagent. Fig. 4.1 shows some reactions of propanone and its derivatives. Reaction 1 is a nucleophilic addition reaction.

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• Question 39Oct/Nov 2023, paper 11Multiple choice1 markHas a diagram

  The infrared spectrum of compound L is shown.

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• Question 39May/June 2026, paper 13Multiple choice1 markHas a diagram

  The infrared spectrum of compound X is shown.

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• Question 3Oct/Nov 2025, paper 21Structured13 marksHas a diagram

  Cycloalkanes show similar chemical properties to alkanes but have the same empirical formula as alkenes.

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• Question 4Oct/Nov 2024, paper 22Structured17 marksHas a diagram

  Bromoalkanes are used widely in industry, although there is increasing concern about their environmental impact. Fig. 4.1 shows a reaction scheme involving 1,2-dibromoethane. Complete Fig. 4.2 to show the mechanism for the formation of 1,2-dibromoethane in reaction 1.

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• Question 3Oct/Nov 2023, paper 22Structured19 marksHas a diagram

  Phosphoric(V) acid, ${\mathrm{H}}_3{\mathrm{P}\mathrm{O}}_4$, is used in both inorganic and organic reactions. ${\mathrm{H}}_3{\mathrm{P}\mathrm{O}}_4$ is made in a two-step process from phosphorus. step 1 Phosphorus reacts with an excess of oxygen to form a white solid.

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• Question 4May/June 2025, paper 21Structured9 marksHas a diagram

  The structure of vitamin C is shown in Fig. 4.1. Deduce the empirical formula of vitamin C.

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• Question 40May/June 2024, paper 12Multiple choice1 markHas a diagram

  Compound X reacts with acidified ${\text{K}}_2{\text{Cr}}_2{\text{O}}_7$ to form compound Y. The infrared spectrum of compound Y is shown.

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• Question 5May/June 2023, paper 22Structured12 marksHas a diagram

  Describe structural isomerism.

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• Question 5May/June 2025, paper 22Structured5 marksHas a diagram

  The structure of vitamin C is shown in Fig. 5.1. Fig. 5.1 Deduce the empirical formula of vitamin C.

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• Question 5May/June 2025, paper 23Structured14 marksHas a diagram

  W is a colourless liquid. [Fig. 5.1] Deduce the empirical formula of W.

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• Question 6May/June 2024, paper 21Structured14 marksHas a diagram

  $\mathbf{V}$ shows stereoisomerism. Explain what is meant by stereoisomerism.

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• Question 5May/June 2024, paper 23Structured10 marksHas a diagram

  M reacts to form R by the addition of one reagent, as shown in Fig. 5.1. Fig. 5.1 Identify the reagent and conditions for this reaction.

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