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title: "A student prepares a buffer solution by combining \\(50.0\\text{ mL}\\) of \\(0.20\\text{ M }\\text{HC}_3\\text{H}_5\\text{O}_2\\text{(aq)}\\) and \\(50.0\\text{ mL}\\) of \\(0.20\\text{ M }\\text{NaC}_3\\text{H}_5\\text{O}_2\\text{(aq)}\\). To this buffer, a few drops of \\(6.0\\text{ M }\\text{HCl(aq)}\\) are added, resulting in only a negligible decrease in \\(\\text{pH}\\). Which of the following is the net ionic equation that best represents the primary reaction responsible for resisting the \\(\\text{pH}\\) change upon addition of the acid?"
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url: "https://nerd-notes.com/ubq/119716/"
date_modified: "2026-08-21T08:12:08+00:00"
---

# A student prepares a buffer solution by combining \(50.0\text{ mL}\) of \(0.20\text{ M }\text{HC}_3\text{H}_5\text{O}_2\text{(aq)}\) and \(50.0\text{ mL}\) of \(0.20\text{ M }\text{NaC}_3\text{H}_5\text{O}_2\text{(aq)}\). To this buffer, a few drops of \(6.0\text{ M }\text{HCl(aq)}\) are added, resulting in only a negligible decrease in \(\text{pH}\). Which of the following is the net ionic equation that best represents the primary reaction responsible for resisting the \(\text{pH}\) change upon addition of the acid?

A student prepares a buffer solution by combining \(50.0\text{ mL}\) of \(0.20\text{ M }\text{HC}_3\text{H}_5\text{O}_2\text{(aq)}\) and \(50.0\text{ mL}\) of \(0.20\text{ M }\text{NaC}_3\text{H}_5\text{O}_2\text{(aq)}\). To this buffer, a few drops of \(6.0\text{ M }\text{HCl(aq)}\) are added, resulting in only a negligible decrease in \(\text{pH}\). Which of the following is the net ionic equation that best represents the primary reaction responsible for resisting the \(\text{pH}\) change upon addition of the acid?

- **A.** \(\text{NaC}_3\text{H}_5\text{O}_2\text{(aq)} + \text{HCl(aq)} \rightarrow \text{HC}_3\text{H}_5\text{O}_2\text{(aq)} + \text{NaCl(aq)}\)
- **B.** \(\text{OH}^-\text{(aq)} + \text{H}_3\text{O}^+\text{(aq)} \rightarrow 2\text{ H}_2\text{O(l)}\)
- **C.** \(\text{C}_3\text{H}_5\text{O}_2^-\text{(aq)} + \text{H}_3\text{O}^+\text{(aq)} \rightarrow \text{HC}_3\text{H}_5\text{O}_2\text{(aq)} + \text{H}_2\text{O(l)}\)
- **D.** \(\text{HC}_3\text{H}_5\text{O}_2\text{(aq)} + \text{H}_2\text{O(l)} \rightleftharpoons \text{C}_3\text{H}_5\text{O}_2^-\text{(aq)} + \text{H}_3\text{O}^+\text{(aq)}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119716/*