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The table lists the information from a proton NMR spectrum - HSC - SSCE Chemistry - Question 18 - 2021 - Paper 1
Question 18
The table lists the information from a proton NMR spectrum. | Chemical shift (ppm) | Multiplicity | Number of hydrogens | |-----------------------|--------------|--... show full transcript
Worked Solution & Example Answer:The table lists the information from a proton NMR spectrum - HSC - SSCE Chemistry - Question 18 - 2021 - Paper 1
Step 1
Analyze the Chemical Shifts and Multiplicities
Answer
The chemical shifts and their corresponding multiplicities indicate specific hydrogen environments. The triplet at 1.0 ppm suggests the presence of three equivalent protons that are being affected by two neighboring protons. The singlet at 1.4 ppm indicates three protons that are not adjacent to any other protons. Finally, the quartet at 1.8 ppm suggests two protons influenced by three neighboring protons.
Step 2
Evaluate Compound Options
Answer
Now we need to assess the given compounds:
- A. 1,2,2-trichlorobutane: This has multiple chlorine substituents affecting the shifts but does not fit the provided spectrum's descriptors.
- B. 1,3-dichloro-2-methylpropane: Similar reasoning applies; the spectrum does not support this compound.
- C. 2-chloro-2-methylbutane: The structure involves protons that don't match with the multiplicity indicated in the spectrum.
- D. 2,2-dichlorobutane: This compound can produce the observed triplet, singlet, and quartet patterns with the corresponding chemical shifts.
Step 3