ASChemistryCambridge (CIE)Exam Questions22. Analytical TechniquesInfrared Spectroscopy

Infrared Spectroscopy (Cambridge (CIE) AS Chemistry): Exam Questions

Exam code: 9701

1 hour16 questions

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Infrared Spectroscopy

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1
1 mark

Which of the following statements about propanal, CH3CH2CHO, and propanone, CH3COCH3, is not correct?

  • They have a different fingerprint region in the infrared spectrum.

  • They have absorption in the infrared spectrum due to the carbonyl group.

  • They have different fragmentation patterns in the mass spectrum.

  • They have molecular ion peaks at different mass to charge ratios.

Choose your answer

2
1 mark

Which of the following cannot be obtained from an infrared spectrum?

  • The identity of a compound through comparison with other spectra

  • The molecular mass

  • The presence of C=O bonds

  • The presence of O-H bonds

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3
1 mark

Which type of organic compound could have produced the infrared spectrum shown?

IR spectrum showing a broad absorption from 2500 to 3000 cm-1 and a strong absorption at approximately 1700 cm-1

  • Alcohol

  • Aldehyde

  • Carboxylic acid

  • Ketone

Choose your answer

1
1 mark

The infrared spectrum of a compound is shown below.

IR spectrum showing a strong absorption at approximately 1700 cm-1 with no O-H absorption

Which compound is shown by the infrared spectrum?

  • Propan-1-ol

  • Propan-2-ol

  • Propanal

  • Propanone

Choose your answer

2
1 mark

The infrared spectrum of a compound is shown below.

IR spectrum showing a strong absorption at approximately 1720 cm-1 with no O-H absorption

Which compound is shown by the infrared spectrum?

  • But-1-ene

  • Butan-1-ol

  • Butanal

  • Butanoic acid

Choose your answer

3
1 mark

Which class of compound does not contain the functional group responsible for the strong absorption between 1670 cm-1 and 1740 cm-1?

  • Alcohol

  • Aldehyde

  • Carboxylic acid

  • Ketone

Choose your answer

1
1 mark

The infrared spectrum below shows an unknown compound.

IR spectrum showing a sharp O-H absorption at 3200 to 3600 cm-1 and a strong C=O absorption at approximately 1700 to 1740 cm-1, with complex fingerprint region absorptions

Which compound could have produced the infrared spectrum?

  • Skeletal formula of butanoic acid
  • Skeletal formula of 4-hydroxybutan-2-one
  • Skeletal formula of pent-4-en-1-ol
  • Skeletal formula of pent-4-en-2-one

Choose your answer

2
1 mark

The infrared spectrum below shows an unknown compound.

IR spectrum showing C-H absorptions at 2700 to 2950 cm-1 including a characteristic aldehyde C-H doublet, and a strong C=O absorption at approximately 1720 cm-1 with no O-H absorption

Which compound would give this spectrum?

  • 1-bromobutane

  • Butan-1-ol

  • Butanal

  • Butanoic acid

Choose your answer

3
1 mark

Which of the following infrared spectra could show a carboxylic acid?

  • A spectrum showing broad O-H absorption from 2500 to 3000 cm-1 and a C=O absorption, consistent with a carboxylic acid
  • A spectrum showing sharp O-H absorption at 3200 to 3600 cm-1 with no C=O, consistent with an alcohol
  • A spectrum showing strong C=O absorption and C-O absorption in the fingerprint region, consistent with an ester
  • A spectrum showing strong C=O absorption at approximately 1710 cm-1 only, consistent with a ketone

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