---
title: "A student compares three carboxylic acids: acetic acid (\\(\\text{CH}_3\\text{COOH}\\)), fluoroacetic acid (\\(\\text{CH}_2\\text{FCOOH}\\)), and trichloroacetic acid (\\(\\text{CCl}_3\\text{COOH}\\)). Separate \\(0.10\\text{ M}\\) aqueous solutions of each acid are prepared at \\(25^\\circ\\text{C}\\). Which of the following lists the acids in order of decreasing percent ionization, and provides the best explanation?"
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url: "https://nerd-notes.com/ubq/123781/"
date_modified: "2026-09-28T12:30:17+00:00"
---

# A student compares three carboxylic acids: acetic acid (\(\text{CH}_3\text{COOH}\)), fluoroacetic acid (\(\text{CH}_2\text{FCOOH}\)), and trichloroacetic acid (\(\text{CCl}_3\text{COOH}\)). Separate \(0.10\text{ M}\) aqueous solutions of each acid are prepared at \(25^\circ\text{C}\). Which of the following lists the acids in order of decreasing percent ionization, and provides the best explanation?

A student compares three carboxylic acids: acetic acid (\(\text{CH}_3\text{COOH}\)), fluoroacetic acid (\(\text{CH}_2\text{FCOOH}\)), and trichloroacetic acid (\(\text{CCl}_3\text{COOH}\)). Separate \(0.10\text{ M}\) aqueous solutions of each acid are prepared at \(25^\circ\text{C}\). Which of the following lists the acids in order of decreasing percent ionization, and provides the best explanation?

- **A.** \(\text{CCl}_3\text{COOH} > \text{CH}_2\text{FCOOH} > \text{CH}_3\text{COOH}\), because the conjugate base of \(\text{CCl}_3\text{COOH}\) is stabilized by additional resonance structures involving the three chlorine atoms.
- **B.** \(\text{CCl}_3\text{COOH} > \text{CH}_2\text{FCOOH} > \text{CH}_3\text{COOH}\), because the three electronegative \(\text{Cl}\) atoms exert a greater cumulative electron-withdrawing inductive effect than a single \(\text{F}\) atom, which more effectively delocalizes negative charge in the conjugate base.
- **C.** \(\text{CH}_2\text{FCOOH} > \text{CCl}_3\text{COOH} > \text{CH}_3\text{COOH}\), because \(\text{F}\) has a higher electronegativity than \(\text{Cl}\), making the inductive electron withdrawal of a single \(\text{F}\) atom stronger than that of three \(\text{Cl}\) atoms combined.
- **D.** \(\text{CH}_2\text{FCOOH} > \text{CCl}_3\text{COOH} > \text{CH}_3\text{COOH}\), because the smaller atomic size of \(\text{F}\) allows greater \(\pi\)-orbital overlap with the carboxyl group, providing greater resonance stabilization to the conjugate base.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/123781/*