This question is about compound X with the empirical formula C2H6O - AQA - A-Level Chemistry - Question 6 - 2022 - Paper 2
Question 6
This question is about compound X with the empirical formula C2H6O.
Figure 2 shows the infrared spectrum of X.
Figure 3 shows the 1H NMR spectrum of X.
The 1H NMR... show full transcript
Worked Solution & Example Answer:This question is about compound X with the empirical formula C2H6O - AQA - A-Level Chemistry - Question 6 - 2022 - Paper 2
Step 1
Chemical shift δ / ppm: 3.9
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Answer
This peak at 3.9 ppm corresponds to a hydrogen atom bonded to a carbon that is adjacent to an electronegative oxygen atom. This suggests the presence of a hydroxyl (–OH) group or an ether. Given the empirical formula C2H6O, this peak supports the presence of a hydroxyl group.
Step 2
Chemical shift δ / ppm: 3.7
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The peak at 3.7 ppm is indicative of a hydrogen atom in a carbon bond that is part of an alkyl group adjacent to another carbon or functional group. This further confirms the alkyl structure in the compound.
Step 3
Chemical shift δ / ppm: 2.1
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The peak at 2.1 ppm, aligning with a singlet, suggests that there are protons coming from a methyl group (–CH3) that are not adjacent to any other hydrogens. This supports the presence of at least one methyl group in the molecular structure.
Step 4
Chemical shift δ / ppm: 1.2
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Answer
The peak at 1.2 ppm corresponds to a doublet, indicating neighboring protons. This is consistent with protons from a –CH2– group that is next to another carbon chain; thus, supporting the existence of an ethyl group (–CH2–CH3) or a methyl connected to the main chain.
