At what m/z would the base peak of (E)-2-hexene occur?

Question

Quizplus · Accepted Answer

The base peak in a mass spectrum is the tallest peak, which represents the most abundant fragment ion. To determine the base peak for (E)-2-hexene, we need to consider the possible fragmentation pathways of the molecule. One common fragmentation in mass spectrometry is the loss of a methyl group (CH3). If (E)-2-hexene loses a methyl group, it would form a 1-pentenyl cation (C5H9+). This cation could then lose a hydrogen ion (H+) to form a stable allyl cation (C3H5+), which would likely be observed as the base peak in the mass spectrum. The mass of the allyl cation is 55 amu, so the correct answer is C.

At What M/z Would the Base Peak of (E)-2-Hexene Occur