---
title: "A buffer solution is prepared by mixing equimolar amounts of a weak acid, \\(\\text{HA}\\), and its conjugate base, \\(\\text{A}^-\\). The particulate diagram below represents a sample of this initial buffer solution containing exactly \\(5\\) molecules of \\(\\text{HA}\\) and \\(5\\) ions of \\(\\text{A}^-\\). A student adds a solution containing exactly \\(2\\) units of \\(\\text{H}_3\\text{O}^+\\) to this sample.  Which of the following particulate diagrams best represents the resulting mixture after the acid-base reaction goes to completion?"
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url: "https://nerd-notes.com/ubq/123881/"
date_modified: "2026-09-28T12:30:45+00:00"
---

# A buffer solution is prepared by mixing equimolar amounts of a weak acid, \(\text{HA}\), and its conjugate base, \(\text{A}^-\). The particulate diagram below represents a sample of this initial buffer solution containing exactly \(5\) molecules of \(\text{HA}\) and \(5\) ions of \(\text{A}^-\). A student adds a solution containing exactly \(2\) units of \(\text{H}_3\text{O}^+\) to this sample.

Which of the following particulate diagrams best represents the resulting mixture after the acid-base reaction goes to completion?

A buffer solution is prepared by mixing equimolar amounts of a weak acid, \(\text{HA}\), and its conjugate base, \(\text{A}^-\). The particulate diagram below represents a sample of this initial buffer solution containing exactly \(5\) molecules of \(\text{HA}\) and \(5\) ions of \(\text{A}^-\). A student adds a solution containing exactly \(2\) units of \(\text{H}_3\text{O}^+\) to this sample.

Which of the following particulate diagrams best represents the resulting mixture after the acid-base reaction goes to completion?

![A single square box represents a buffer solution sample. A legend at the top maps: open circle = \(\text{HA}\), filled black circle = \(\text{A}^-\). Inside the square container, there are exactly 5 open circles and exactly 5 filled black circles evenly distributed without overlap. Water molecules and spectator ions are omitted. No other particles, labels, text, or annotations appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1790598643-Az7Iyz.jpg)

- **A.** Diagram A
- **B.** Diagram B
- **C.** Diagram C
- **D.** Diagram D

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/123881/*