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Spectroscopy

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Question 2

Analysis of an unknown organic compound L produces the following results.

Elemental analysis by mass of compound L

  • Carbon (C): 72.00%
  • Hydrogen (H): 6.67%
  • Oxygen (O): 21.33%

Mass spectrum of compound L

  • Key peaks at m/z=150m/z = 150m/z=150 (molecular ion peak), 105 (base peak), and 77.

IR spectrum of compound L

  • Strong absorption at 1720 cm-1
  • Strong absorption at 1275 cm-1
  • Absorptions at 1600 cm-1 and 1450 cm-1
  • Absorptions just above and just below 3000 cm-1

Proton (1H^1\text{H}1H) NMR spectrum of compound L

  • Multiplet at δ=7.4−8.1 ppm\delta = 7.4 - 8.1\text{ ppm}δ=7.4−8.1 ppm, relative peak area = 5
  • Quartet at δ=4.4 ppm\delta = 4.4\text{ ppm}δ=4.4 ppm, relative peak area = 2
  • Triplet at δ=1.4 ppm\delta = 1.4\text{ ppm}δ=1.4 ppm, relative peak area = 3

Determine the structure of compound L, showing all your reasoning.

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Markscheme

Spectroscopy Questions

  1. A Level
  2. /Chemistry
  3. /Spectroscopy

28 exam-style questions on OCR A A Level Chemistry Spectroscopy. Each one has a worked solution and a mark scheme showing where the marks go.

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