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Analytical techniques: OCR A‑Level Chemistry A questions

Every OCR A-Level Chemistry A exam question on 4.2.4 Analytical techniques, 2016–2025, with its mark scheme and examiner’s report.

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1,820 questions

  1. Q11

    June 2025 · Paper 2

    1 mark4.2.4 Analytical techniques
    The whole paper ↗
    June 2025 Paper 2, question 11: Which molecule does not produce a mass spectrum containing a peak at m/z = 29? OH A O B O C O O D O OH Your answer [1]

  2. Q12

    June 2025 · Paper 2

    1 mark4.2.4 Analytical techniques
    The whole paper ↗
    June 2025 Paper 2, question 12: Which process does not involve infrared radiation? A Catalytic ozone depletion B Monitoring toxic gases in the air C Measuring ethanol in breathalyser tests D G

  3. Q19

    June 2025 · AS Paper 1

    1 mark4.2.4 Analytical techniques
    The whole paper ↗
    June 2025 AS Paper 1, question 19: In a mass spectrum, which alkene is likely to have a fragment ion at m / z = 29? A H2C=CHCH=CH2 B H2C=C(CH3)2 C H3CCH=CHCH3 D H3CCH=CHCH2CH3 Your answer [1]

  4. Q20

    June 2025 · AS Paper 1

    1 mark4.2.4 Analytical techniques
    The whole paper ↗
    June 2025 AS Paper 1, question 20: The IR spectrum of a compound is shown below. 100 80 60 transmittance (%) 40 20 0 4000 3000 2000 1500 1000 400 wavenumber / cm–1 Which compound could have produ

  5. Q6(a)(i)

    June 2025 · AS Paper 2

    2 marks4.2.4 Analytical techniques
    The whole paper ↗
    June 2025 AS Paper 2, question 6(a)(i): Draw structures for the ions responsible for peak P and peak Q. ion responsible for peak P ion responsible for peak Q [2]

  6. Q6(a)(ii)

    June 2025 · AS Paper 2

    1 mark4.2.4 Analytical techniques
    The whole paper ↗
    June 2025 AS Paper 2, question 6(a)(ii): Explain why there is a small peak at m / z = 73 [1]

  7. Q6(b)(i)

    June 2025 · AS Paper 2

    1 mark4.2.4 Analytical techniques
    The whole paper ↗
    June 2025 AS Paper 2, question 6(b)(i): State the effect infrared radiation has on covalent bonds. [1]

  8. Q6(b)(ii)

    June 2025 · AS Paper 2

    2 marks4.2.4 Analytical techniques
    The whole paper ↗
    June 2025 AS Paper 2, question 6(b)(ii): Identify two functional groups which are likely to be present in Compound B but are not present in Compound A. Explain your answers. Functional group Explanatio

  9. Q7

    June 2024 · Paper 2

    1 mark4.2.4 Analytical techniques
    The whole paper ↗
    June 2024 Paper 2, question 7: Which statement gives a valid scientific reason for global warming? A Infrared radiation causes bonds in CH4 molecules to vibrate more. B Infrared radiation cau

  10. Q11

    June 2024 · Paper 2

    1 mark4.2.4 Analytical techniques
    The whole paper ↗
    June 2024 Paper 2, question 11: Which compound could have produced the IR spectrum shown below? 100 Transmittance 50 (%) 0 4000 3000 2000 1500 1000 500 Wavenumber / cm–1 A HOCH2CHO B CH3CH2COO

  11. Q19

    June 2024 · AS Paper 1

    1 mark4.2.4 Analytical techniques
    The whole paper ↗
    June 2024 AS Paper 1, question 19: Which statement about infrared radiation (IR) is not correct? A Absorption of IR by molecules such as CO2, H2O and CH4 has been linked to global warming. B IR c

  12. Q20

    June 2024 · AS Paper 1

    1 mark4.2.4 Analytical techniques
    The whole paper ↗
    June 2024 AS Paper 1, question 20: An alcohol CH3CH2CH(CH3)OH produces a mass spectrum. The mass spectrum contains a large fragment ion at m/z = 45. What is the possible identity of this fragment

  13. Q6

    June 2024 · AS Paper 2

    6 marks4.2.4 Analytical techniques
    The whole paper ↗
    June 2024 AS Paper 2, question 6: 6* Compound X is an organic compound with two functional groups. Compound X has the percentage composition by mass: C, 40.91%; H, 4.54%; O, 54.55%. Compound X d

  14. Q10

    June 2023 · Paper 2

    1 mark4.2.4 Analytical techniques
    The whole paper ↗
    June 2023 Paper 2, question 10: Which ester is most likely to produce a mass spectrum with a fragment ion at m / z = 43? OH O A H3C C C O CH3 CH3 O B HO CH2 C O CH2CH2CH3 OH O C H3C CH CH2 C O

  15. Q11

    June 2023 · Paper 2

    1 mark4.2.4 Analytical techniques
    The whole paper ↗
    June 2023 Paper 2, question 11: The infrared spectrum of an organic compound is shown below. 100 transmittance (%) 50 0 4000 3000 2000 1500 1000 500 wavenumber / cm–1 Which compound could have

  16. Q19

    June 2023 · AS Paper 1

    1 mark4.2.4 Analytical techniques
    The whole paper ↗
    June 2023 AS Paper 1, question 19: An organic compound produces the infrared spectrum below. 100 transmittance 50 (%) 0 4000 3000 2000 1500 1000 500 wavenumber / cm–1 Which compound could have pr

  17. Q20

    June 2023 · AS Paper 1

    1 mark4.2.4 Analytical techniques
    The whole paper ↗
    June 2023 AS Paper 1, question 20: Pentan-2-ol and pentan-3-ol are structural isomers with the molecular formula C5H12O and Mr = 88. The isomers can be distinguished from the fragment ions in the

  18. Q2

    June 2022 · Paper 2

    1 mark4.2.4 Analytical techniques4.1.3 Alkenes
    The whole paper ↗
    June 2022 Paper 2, question 2: Which statement about absorption of radiation is correct? A Infrared radiation can result in the breakdown of the ozone layer. B Ultraviolet radiation can cause

  19. Q11

    June 2022 · Paper 2

    1 mark4.2.4 Analytical techniques
    The whole paper ↗
    June 2022 Paper 2, question 11: The infrared spectrum of an organic compound is shown below. 100 Transmittance (%) 0 4000 3000 2000 1500 1000 500 Wavenumber / cm–1 Which compound could have pr

  20. Q18(b)

    June 2022 · Paper 2

    4 marks2.1.3 Amount of substance4.2.4 Analytical techniques
    The whole paper ↗
    June 2022 Paper 2, question 18(b): A student is provided with two unknown carbonyl compounds, F and G. The compounds are analysed and found to have identical percentage compositions by mass: C: 6
All 49 questions on Analytical techniques, as a list
  1. June 2025, Paper 2, Q11 (1 mark): Which molecule does not produce a mass spectrum containing a peak at m/z = 29? OH A O B O C O O D O OH Your answer [1]
  2. June 2025, Paper 2, Q12 (1 mark): Which process does not involve infrared radiation? A Catalytic ozone depletion B Monitoring toxic gases in the air C Measuring ethanol in breathalyser tests D G
  3. June 2025, AS Paper 1, Q19 (1 mark): In a mass spectrum, which alkene is likely to have a fragment ion at m / z = 29? A H2C=CHCH=CH2 B H2C=C(CH3)2 C H3CCH=CHCH3 D H3CCH=CHCH2CH3 Your answer [1]
  4. June 2025, AS Paper 1, Q20 (1 mark): The IR spectrum of a compound is shown below. 100 80 60 transmittance (%) 40 20 0 4000 3000 2000 1500 1000 400 wavenumber / cm–1 Which compound could have produ
  5. June 2025, AS Paper 2, Q6(a)(i) (2 marks): Draw structures for the ions responsible for peak P and peak Q. ion responsible for peak P ion responsible for peak Q [2]
  6. June 2025, AS Paper 2, Q6(a)(ii) (1 mark): Explain why there is a small peak at m / z = 73 [1]
  7. June 2025, AS Paper 2, Q6(b)(i) (1 mark): State the effect infrared radiation has on covalent bonds. [1]
  8. June 2025, AS Paper 2, Q6(b)(ii) (2 marks): Identify two functional groups which are likely to be present in Compound B but are not present in Compound A. Explain your answers. Functional group Explanatio
  9. June 2024, Paper 2, Q7 (1 mark): Which statement gives a valid scientific reason for global warming? A Infrared radiation causes bonds in CH4 molecules to vibrate more. B Infrared radiation cau
  10. June 2024, Paper 2, Q11 (1 mark): Which compound could have produced the IR spectrum shown below? 100 Transmittance 50 (%) 0 4000 3000 2000 1500 1000 500 Wavenumber / cm–1 A HOCH2CHO B CH3CH2COO
  11. June 2024, AS Paper 1, Q19 (1 mark): Which statement about infrared radiation (IR) is not correct? A Absorption of IR by molecules such as CO2, H2O and CH4 has been linked to global warming. B IR c
  12. June 2024, AS Paper 1, Q20 (1 mark): An alcohol CH3CH2CH(CH3)OH produces a mass spectrum. The mass spectrum contains a large fragment ion at m/z = 45. What is the possible identity of this fragment
  13. June 2024, AS Paper 2, Q6 (6 marks): 6* Compound X is an organic compound with two functional groups. Compound X has the percentage composition by mass: C, 40.91%; H, 4.54%; O, 54.55%. Compound X d
  14. June 2023, Paper 2, Q10 (1 mark): Which ester is most likely to produce a mass spectrum with a fragment ion at m / z = 43? OH O A H3C C C O CH3 CH3 O B HO CH2 C O CH2CH2CH3 OH O C H3C CH CH2 C O
  15. June 2023, Paper 2, Q11 (1 mark): The infrared spectrum of an organic compound is shown below. 100 transmittance (%) 50 0 4000 3000 2000 1500 1000 500 wavenumber / cm–1 Which compound could have
  16. June 2023, AS Paper 1, Q19 (1 mark): An organic compound produces the infrared spectrum below. 100 transmittance 50 (%) 0 4000 3000 2000 1500 1000 500 wavenumber / cm–1 Which compound could have pr
  17. June 2023, AS Paper 1, Q20 (1 mark): Pentan-2-ol and pentan-3-ol are structural isomers with the molecular formula C5H12O and Mr = 88. The isomers can be distinguished from the fragment ions in the
  18. June 2022, Paper 2, Q2 (1 mark): Which statement about absorption of radiation is correct? A Infrared radiation can result in the breakdown of the ozone layer. B Ultraviolet radiation can cause
  19. June 2022, Paper 2, Q11 (1 mark): The infrared spectrum of an organic compound is shown below. 100 Transmittance (%) 0 4000 3000 2000 1500 1000 500 Wavenumber / cm–1 Which compound could have pr
  20. June 2022, Paper 2, Q18(b) (4 marks): A student is provided with two unknown carbonyl compounds, F and G. The compounds are analysed and found to have identical percentage compositions by mass: C: 6
  21. June 2022, AS Paper 1, Q19 (1 mark): Which organic compound could have produced the infrared spectrum below? 100 transmittance 50 (%) 0 4000 3000 2000 1500 1000 500 wavenumber / cm–1 A CH3COCH2CH3
  22. June 2022, AS Paper 1, Q20 (1 mark): Which alcohol is likely to have fragment ions at m / z = 15, 29 and 43 in its mass spectrum? OH A B OH OH C OH D Your answer [1]
  23. June 2022, AS Paper 2, Q6 (6 marks): 6* The organic compound A is unsaturated and is a trans stereoisomer. Compound A has the following composition by mass: C, 55.8%; H, 7.0%; O, 37.2%. The mass sp
  24. November 2021, Paper 2, Q11 (1 mark): Which compound could have produced the IR spectrum below? 100 transmittance (%) 50 0 4000 3000 2000 1500 1000 500 wavenumber / cm–1 A (CH3)2CHCHO B (CH3)2CHCOOH
  25. November 2021, Paper 2, Q12 (1 mark): Which peak would be in the mass spectrum of propanal, CH3CH2CHO, but not in the mass spectrum of propanone, CH3COCH3? A m /z = 15 B m /z = 29 C m /z = 43 D m /z
  26. November 2021, AS Paper 1, Q19 (1 mark): Which statement about absorption of radiation is correct? A Absorption of IR radiation can break covalent bonds, forming radicals. B Absorption of IR radiation
  27. November 2021, AS Paper 1, Q26 (5 marks): An organic compound E contains C, H and O only. The mass and infrared spectra of organic compound E are shown below. Mass spectrum 100 80 60 relative intensity
  28. November 2020, Paper 2, Q20(b) (2 marks): The organic layer in the distillate was analysed by IR spectroscopy. The IR spectrum is shown below. 100 Transmittance (%) 50 0 4000 3000 2000 1500 1000 500 Wav
  29. November 2020, AS Paper 1, Q20 (1 mark): The mass spectrum of a carboxylic acid contains peaks at m /z = 29 and m /z = 102. Which compound could have produced the spectrum? O A OH OH B O OH C O OH D O
  30. June 2019, Paper 2, Q18(e)(ii) (2 marks): The mass spectrum of ester C is shown below. 100 Y 80 60 Relative intensity 40 Z 20 0 10 20 30 40 50 60 70 80 90 100 m / z Suggest possible structures for the s
  31. June 2019, AS Paper 1, Q18 (1 mark): Which compound is not likely to have a fragment ion at m / z = 43 in its mass spectrum? H H O A H C C C OH H H H O H C C B OH H H CH3 H H C C C OH C H H H H H H
  32. June 2019, AS Paper 1, Q19 (1 mark): Which statement about infrared radiation is not correct? A The energy from IR radiation causes some covalent bonds to vibrate more. B Absorption of IR radiation
  33. June 2019, AS Paper 1, Q20 (1 mark): An unknown compound produces the infrared spectrum below. 100 transmittance 50 (%) 0 4000 3000 2000 1500 1000 500 wavenumber / cm–1 Which compound could have pr
  34. June 2019, AS Paper 2, Q3(b)(i) (1 mark): What information is given by the peak labelled X (m/z = 198)? [1]
  35. June 2019, AS Paper 2, Q3(b)(ii) (2 marks): Write the structural formulae of the ions responsible for the peaks labelled Y and Z. Y (m/z = 71) Z (m/z = 43) [2]
  36. June 2019, AS Paper 2, Q3(c)(ii) (2 marks): Suggest one similarity and one difference between the mass spectra of 1-iodopentane and 2-iodo-2-methylbutane. Similarity Difference [2]
  37. June 2018, Paper 2, Q9 (1 mark): Which compound could have produced the IR spectrum below? 100 transmittance (%) 50 0 4000 3000 2000 1500 1000 500 wavenumber / cm–1 A CH3CH2OH B CH3CHOHCN C CH3
  38. June 2018, Paper 2, Q12 (1 mark): The mass spectrum of (CH3)2CHCH2OH is shown below. 100 80 60 relative intensity 40 20 0 10 20 30 40 50 60 70 80 90 m /z Which ion is responsible for the peak wi
  39. June 2018, Paper 2, Q21(c)(ii) (3 marks): A general structure for esters J, L and M is shown below. O C R O HO Where ‘R’ is an alkyl group. Use the mass spectrometry results to deduce possible structure
  40. June 2018, AS Paper 1, Q20 (1 mark): Which alcohol is likely to have a fragment ion at m / z = 31 in its mass spectrum? A CH3CH2CH(OH)CH3 B CH3CH2CH2C(OH)(CH3)2 C CH3CH(OH)CH2CH2CH3 D (CH3)2CHCH2OH
  41. June 2018, AS Paper 1, Q25(b)(ii) (2 marks): The infrared (IR) spectrum for C2H5CHBrCH3 is shown in Fig. 25.2. The C–Br bond absorption is labelled. 100 transmittance 50 (%) C–Br 0 4000 3000 2000 1500 1000
  42. June 2018, AS Paper 2, Q7 (6 marks): 7* Compound F is a trans stereoisomer which is a useful intermediate in organic synthesis. The results of elemental and spectral analysis of compound F are show
  43. June 2017, Paper 2, Q20(a) (3 marks): The percentage composition and mass spectrum of the compound are shown below. Percentage composition by mass: C, 70.58%; H, 5.92%; O, 23.50%. Mass spectrum 100
  44. June 2017, Paper 3, Q1(b) (1 mark): Why are scientists concerned about the release of methane into the atmosphere? [1]
  45. June 2017, AS Paper 1, Q19 (1 mark): An alcohol A is heated under reflux with sulfuric acid and potassium dichromate(VI). The organic compound formed produces the infrared spectrum below. 100 trans
  46. June 2017, AS Paper 1, Q20 (1 mark): Which alcohol is not likely to have a fragment ion at m / z = 43 in its mass spectrum? A CH3CH2CH(OH)CH3 B CH3CH2CH2CH2OH C CH3CH(OH)CH2CH2CH3 D (CH3)2CHCH2OH Y
  47. June 2017, AS Paper 2, Q4(b)(ii) (2 marks): The mass spectrum of alcohol C is shown below. Item removed due to third party copyright restrictions. Write structural formulae for the ions responsible for pe
  48. June 2017, AS Paper 2, Q5(c) (4 marks): Compound D is a neutral compound which is a structural isomer of propanoic acid, CH3CH2COOH. The infrared spectrum of compound D is shown below. Item removed du
  49. June 2016, AS Paper 2, Q7 (6 marks): 7* Organic compound C has the following percentage composition by mass: C, 54.5%; H, 9.1%; O, 36.4%. The infrared spectrum and mass spectrum of compound C are s

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