The mass spectrum and carbon-13 NMR for an organic compound are shown. Mass spectrum Relative intensity 100 80 60 40 20 0 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 m/z Carbon-13 NMR 220 200 180 160 140 120 100 80 60 40 20 0 ppm Question 12 continues on page 9 Question 12 (continued) Which compound could produce the two spectra?

SSCE HSC Chemistry Functional Group Compounds: The mass spectrum and carbon-13

The mass spectrum and carbon-13 NMR for an organic compound are shown - HSC - SSCE Chemistry - Question 12 - 2021 - Paper 1

Question 12

The mass spectrum and carbon-13 NMR for an organic compound are shown. Mass spectrum Relative intensity 100 80 60 40 20 0 10 15 20 25 30 35 40 45 50 55 60 65 70 ... show full transcript

Worked Solution & Example Answer:The mass spectrum and carbon-13 NMR for an organic compound are shown - HSC - SSCE Chemistry - Question 12 - 2021 - Paper 1

Step 1

Which compound could produce the two spectra?

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Answer

To determine which compound produces the provided mass spectrum and carbon-13 NMR, we need to analyze both spectra.

Analyzing the Mass Spectrum

Peak Identification: Observe the major peaks in the mass spectrum. The peaks at m/z 42, 55, and 98 are notable, suggesting possible fragments or molecular ion signals.
Fragmentation Patterns: The m/z values can help infer the presence of functional groups or structural characteristics in the compound.

Analyzing the Carbon-13 NMR

Chemical Shifts: The NMR shows peaks at specific ppm values. A common peak near 0-40 ppm typically indicates alkane or methyl groups, while higher values indicate carbonyl or aromatic signals.
Peak Splitting and Integration: Evaluate the number of unique carbon environments, which will reveal how many different types of carbons are present in the compound.

Comparing with Options A-D

Compare the observed m/z ratios and peaks in both the mass spectrum and carbon-13 NMR against the proposed structures (A-D).

Identification

After evaluating all the options, the compound represented by option A matches the spectra. This indicates that the spectra are characteristic of the functional groups and fragmentation patterns present in option A.