what type of feature will be observd in the ei mass spectrum of chlorobenzene?
you will notice the lines always reflect the two isotopes of Carbon12, and carbon13.
To determine the type of features observed in the electron ionization (EI) mass spectrum of chlorobenzene, we need to follow the steps:
1. Determine the molecular ion: The first peak in the EI mass spectrum corresponds to the molecular ion (M+), which represents the intact molecular weight of chlorobenzene (C6H5Cl). In chlorobenzene, the chlorine atom (35.5 g/mol) replaces one hydrogen atom from the benzene ring (C6H6→C6H5Cl). Thus, the molecular ion peak in the mass spectrum will be observed at m/z (mass-to-charge ratio) equal to the molecular weight of chlorobenzene.
2. Identify fragment peaks: After the molecular ion peak, the mass spectrum will show fragmentation peaks corresponding to the breakdown of the chlorobenzene molecule. These fragments will vary in intensity depending on the stability of the fragments and the ease of fragmentation.
In chlorobenzene, likely fragmentation pathways involve the cleavage of C-Cl bonds, leading to the formation of different fragment ions. Some common fragments in the EI mass spectrum of chlorobenzene may include:
- A peak at m/z equal to the benzene ring (C6H5+), resulting from the loss of the chlorine atom.
- Peaks corresponding to the loss of smaller fragments, such as HCl (m/z = 36), C2H2 (m/z = 26), and C4H4 (m/z = 52), among others.
3. Analyze further fragmentation patterns: Depending on the instrument sensitivity and resolution, additional fragmentation peaks may be observed in the mass spectrum. These peaks can provide valuable information about the structure and connectivity of the molecule.
By analyzing the EI mass spectrum of chlorobenzene, it is possible to identify characteristic fragment peaks and interpret the fragmentation pathways, providing insights into the molecular structure. Remember that the specific intensities and positions of the peaks may vary depending on the instrument's operating conditions and resolution.