Chapter 16, Problem 16.32YT

Interpretation Introduction

Interpretation:

It is to be verified that the values of m/z for ${\text{M}}^{\text{+}}$ and $\text{M + 2 }$ peaks in figure $16-38$ are consistent with the presence of the ${}^{\text{79}}{\text{Br and }}^{\text{81}}\text{Br}$ isotopes by calculating the molecular masses of both species. Also molecular formula account for the small peak at $\text{m / z = 157}$ and at $\text{m / z = 159}$ is to be determined.

Concept introduction:

The mass of ${}^{\text{79}}\text{Br}$ is $\text{79 u}$, and that of ${}^{\text{81}}\text{Br}$ is $\text{81 u}$; they differ by $\text{2 u}$. The mass of ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}$ portion is $\text{77 u}$, and the $\text{M + 1}$ peak for ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{}^{79}\text{Br }$ is at $\text{m / z = 157}$, and $\text{m / z = 159}$ is the $\text{M + 1}$ peak for ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{}^{\text{81}}\text{Br}$.