The mass spectrum of n-octane shows a prominent molecular ion peak (m/z 114). There is also a large peak of m/z of 57 but it is not the base peak.
a) Write fragmentation reactions that account for the base peak of 57 for both n-octane and 3,4-dimethylhexane.
b) Predict the intensities of the peaks at masses 57 and 114 in the spectrum of 2,2,3,3-tetramethylbutane. Support your answer with its corresponding fragmentation reaction.