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    This is a question from OCR A2 chemistry book
    Compound E is a carboxylic acid with the molecular formula C6H12O2. The proton NMR spectrum of compound E has 3 singlet peaks. Identify compound E.
    The answer given at the back is (Ch3)3CCH2COOH, but if I have been taught correctly this structure should not give 3 singlet peaks.
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    (Original post by dugg)
    This is a question from OCR A2 chemistry book
    Compound E is a carboxylic acid with the molecular formula C6H12O2. The proton NMR spectrum of compound E has 3 singlet peaks. Identify compound E.
    The answer given at the back is (Ch3)3CCH2COOH, but if I have been taught correctly this structure should not give 3 singlet peaks.
    Write out the molecule, it is hexanoic acid.
    One peak is due to CH3 at the start of the molecule. The 4CH2s make one peak as they have the same chemical shift. Then OH makes a peak by itself. Ratio of peaks is 3:8:1
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    (Original post by RasputinReborn)
    Write out the molecule, it is hexanoic acid.
    One peak is due to CH3 at the start of the molecule. The 4CH2s make one peak as they have the same chemical shift. Then OH makes a peak by itself. Ratio of peaks is 3:8:1
    unfortunately this is incorrect ...
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    (Original post by dugg)
    This is a question from OCR A2 chemistry book
    Compound E is a carboxylic acid with the molecular formula C6H12O2. The proton NMR spectrum of compound E has 3 singlet peaks. Identify compound E.
    The answer given at the back is (Ch3)3CCH2COOH, but if I have been taught correctly this structure should not give 3 singlet peaks.
    The first three CH3 groups are all in the same environment and not adjacent to a CH, so give a singlet.

    The middle CH2 is also not adjacent to a carbon with H atoms, so is also a singlet.

    Finally, the COOH proton is a singlet.
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    (Original post by charco)
    The first three CH3 groups are all in the same environment and not adjacent to a CH, so give a singlet.

    The middle CH2 is also not adjacent to a carbon with H atoms, so is also a singlet.

    Finally, the COOH proton is a singlet.
    Ah yes😂, I automatically assumed it was hexanoic acid and didn't pay attention to the question.


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