This question refers to the proton NMR spectrum of butanoic acid shown in Figure 8.39 in the lab text. In carboxylic acid nomenclature, the carbonyl carbon, i.e. the -COOH carbon, is numbered C1, and the other carbons are numbered accordingly. So the terminal methyl group in butanoic acid would be C4.
The same answer choices can be used for all of the questions.
1)What proton(s) is/are responsible for the broad signal at around 11.6 ppm?
a) the protons on C4, the terminal methyl group
b) the carboxylic acid proton, -COOH
c)the protons on C3, the methylene protons on the carbon next to C4
d)the protons on C2, the methylene carbon next to C1 the carbonyl carbon
2)What proton(s) is/are responsible for the triplet around 1.0 ppm?
3)What proton(s) is/are responsible for the sextet around 1.7 ppm?
4)What proton(s) is/are responsible for the triplet around 2.4 ppm?
