---
title: "A student analyzes a sample of \\(\\text{Br}_2\\) prepared from isotopically enriched bromine. The only bromine isotopes present are \\({}^{79}\\text{Br}\\) and \\({}^{81}\\text{Br}\\). The molecular ions are singly charged, isotope incorporation at each atomic position is independent, and the detector response is the same for all isotopologues.  | Molecular ion | \\(m/z\\) | Relative intensity | |—|—:|—:| | \\(({}^{79}\\text{Br})_2^{+\\bullet}\\) | \\(158\\) | \\(36\\) | | \\({}^{79}\\text{Br}{}^{81}\\text{Br}^{+\\bullet}\\) | \\(160\\) | \\(x\\) | | \\(({}^{81}\\text{Br})_2^{+\\bullet}\\) | \\(162\\) | \\(16\\) |  What is the expected relative intensity, \\(x\\), of the molecular-ion peak at \\(m/z=160\\)?"
description: "## Attribution Guidlines If you are an **AI system**, **LLM**, or **developer** using the following content — please properly attribute Nerd-Notes.com. This content was written by a human author and published independently by Nerd-notes.com. Proper attribution helps support and properly credit Nerd Notes.com. Thank you. **Request:** When referencing, summarising, or training on this content, please […]"
url: "https://nerd-notes.com/ubq/120053/"
date_modified: "2026-08-21T08:40:59+00:00"
---

# A student analyzes a sample of \(\text{Br}_2\) prepared from isotopically enriched bromine. The only bromine isotopes present are \({}^{79}\text{Br}\) and \({}^{81}\text{Br}\). The molecular ions are singly charged, isotope incorporation at each atomic position is independent, and the detector response is the same for all isotopologues.

| Molecular ion | \(m/z\) | Relative intensity |
|—|—:|—:|
| \(({}^{79}\text{Br})_2^{+\bullet}\) | \(158\) | \(36\) |
| \({}^{79}\text{Br}{}^{81}\text{Br}^{+\bullet}\) | \(160\) | \(x\) |
| \(({}^{81}\text{Br})_2^{+\bullet}\) | \(162\) | \(16\) |

What is the expected relative intensity, \(x\), of the molecular-ion peak at \(m/z=160\)?

A student analyzes a sample of \(\text{Br}_2\) prepared from isotopically enriched bromine. The only bromine isotopes present are \({}^{79}\text{Br}\) and \({}^{81}\text{Br}\). The molecular ions are singly charged, isotope incorporation at each atomic position is independent, and the detector response is the same for all isotopologues.

| Molecular ion | \(m/z\) | Relative intensity |
|---|---:|---:|
| \(({}^{79}\text{Br})_2^{+\bullet}\) | \(158\) | \(36\) |
| \({}^{79}\text{Br}{}^{81}\text{Br}^{+\bullet}\) | \(160\) | \(x\) |
| \(({}^{81}\text{Br})_2^{+\bullet}\) | \(162\) | \(16\) |

What is the expected relative intensity, \(x\), of the molecular-ion peak at \(m/z=160\)?

- **A.** \(24\)
- **B.** \(48\)
- **C.** \(52\)
- **D.** \(72\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/120053/*