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.
Table 3 gi... 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
The peak at 3.9 ppm in the 1H NMR spectrum indicates the presence of a hydrogen atom attached to a carbon atom that is adjacent to an electronegative atom, likely oxygen. This suggests the presence of an -O-CH2- group, consistent with the empirical formula.
Step 2
Chemical shift δ / ppm: 3.7
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The peak at 3.7 ppm corresponds to a hydrogen atom in a different environment, potentially an -O-CH3 group. This further supports the presence of an alcohol or ether functional group.
Step 3
Chemical shift δ / ppm: 2.1
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The peak at 2.1 ppm is indicative of hydrogen atoms in a more deshielded environment, possibly associated with a methylene (CH2) group. This suggests that we may have the -CH2- connected to another carbon atom or functional group.
Step 4
Chemical shift δ / ppm: 1.2
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The doublet observed at 1.2 ppm implies the presence of terminal methyl groups (CH3) in the molecular structure, reinforcing the presence of a straight-chain or branched hydrocarbon.
Step 5
Deduction of Structure
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Based on the data from the NMR and IR spectra, as well as the peak integration values from Table 3, we can deduce that the structure of compound X is likely to be ethanol (C2H5OH) or a related compound containing similar functional groups, such as an ether or other alcohols. The characteristic peaks and integrations correlate well with a molecular structure suggesting C2H6O.
