Primary alcohols have a strong peak at m/z = 31.
a. What fragment is responsible for this peak?

Show the fragmentations that give rise to the peaks at m/z 43, 57, and 85 in the mass spectrum of 2,4-dimethylpentane (Figure 12-17).

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A laboratory student added 1-bromobutane to a flask containing dry ether and magnesium turnings. An exothermic reaction resulted, and the ether boiled vigorously for several minutes. Then she added acetone to the reaction mixture and the ether boiled even more vigorously. She added dilute acid to the mixture and separated the layers. She evaporated the ether layer, and distilled a liquid that boiled at 143 °C. GC–MS analysis of the distillate showed one major product with a few minor impurities. The mass spectrum of the major product is shown here.

(b) Explain why the molecular ion is or is not visible in the mass spectrum, and show what ions are likely to be responsible for the strong peaks at m/z 59 and 101.

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Using curved arrows, show the principal fragments you would expect to see in the mass spectrum of each of the following compounds:

b.

Using curved arrows, show the principal fragments you would expect to see in the mass spectrum of each of the following compounds:

f.

What distinguishes the mass spectrum of 2,2-dimethylpropane from the mass spectra of pentane and isopentane?

Using curved arrows, show the principal fragments you would expect to see in the mass spectrum of each of the following compounds:

c.

The mass spectra of 1-methoxybutane, 2-methoxybutane, and 2-methoxy-2-methylpropane are shown below. Match each compound with its spectrum.

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The reaction of (Z)-2-pentene with water and a trace of H₂SO₄ forms two products. Identify the products from their mass spectra.

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