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Answers:

Solution for the spektrum

Reasoning

  1. Determine the number and relative intensities of the signals, as well as their expected spectral position.
    Number Groups Relative intensities Expected chemical shift(d)
    3 -CH3 3 0,6 ... 1,9ppm
    -CH2- 2 1,9 ... 3,2ppm
    -CHO 1 9,1...10ppm
  2. Determine the multiplicity of the signals and the relative intensities of the lines in a multiplet.
    Group Coupling with J [Hz] Multiplicity Intensities
    CH3-CH2-CHO CH3-CH2-CHO » 7 3 3/4 : 6/4 : 3/4
    CH3-CH2-CHO CH3-CH2-CHO +
    CH3-CH2-CHO    		 » 7
    » 2    		 4 * 2 = 8 see below
    CH3-CH2-CHO CH3-CH2-CHO » 2 2 1/4 : 2/4 : 1/4
  3. The splitting of the methyl proton signal is as follows:
    splitting
  4. These predictions are in good agreement with the actual experimental spectrum for this molecule:
    experimental spectrum

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