What type of feature will be observed in the EI mass spectrum of chlorobenzene? A)An absorption at 3100 cm^-1 B)A signal at 113 C)A signal at 112 and a signal at 114 in a ratio of 3:1 D)A signal at 112 and a signal at 114 in a ratio of 1:1

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Quizplus · Accepted Answer

The correct answer is C because chlorobenzene has two chlorine isotopes, chlorine-35 and chlorine-37, in a 3:1 ratio. Therefore, in the EI mass spectrum of chlorobenzene, there will be two signals at m/z 112 and m/z 114, with a relative intensity of 3:1. There will also be a signal at m/z 113, which is the average mass of the two isotopes. There will be no absorption at 3100 cm^-1 as this is a vibrational frequency associated with stretching of C-H bonds in an aromatic ring, not a feature of EI mass spectra.

What Type of Feature Will Be Observed in the EI