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title: "A student titrates a \\(50.0 \\text{ mL}\\) sample of \\(0.10 \\text{ M HA(aq)}\\) (\\(K_a = 1.0 \\times 10^{-5}\\)) with \\(0.10 \\text{ M NaOH(aq)}\\) at \\(25\\ ^\\circ\\text{C}\\). After the addition of \\(15.0 \\text{ mL}\\) of \\(0.10 \\text{ M NaOH(aq)}\\), which of the following lists the species in order of decreasing molar concentration in the resulting solution?"
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url: "https://nerd-notes.com/ubq/123782/"
date_modified: "2026-09-28T12:30:17+00:00"
---

# A student titrates a \(50.0 \text{ mL}\) sample of \(0.10 \text{ M HA(aq)}\) (\(K_a = 1.0 \times 10^{-5}\)) with \(0.10 \text{ M NaOH(aq)}\) at \(25\ ^\circ\text{C}\). After the addition of \(15.0 \text{ mL}\) of \(0.10 \text{ M NaOH(aq)}\), which of the following lists the species in order of decreasing molar concentration in the resulting solution?

A student titrates a \(50.0 \text{ mL}\) sample of \(0.10 \text{ M HA(aq)}\) (\(K_a = 1.0 \times 10^{-5}\)) with \(0.10 \text{ M NaOH(aq)}\) at \(25\ ^\circ\text{C}\). After the addition of \(15.0 \text{ mL}\) of \(0.10 \text{ M NaOH(aq)}\), which of the following lists the species in order of decreasing molar concentration in the resulting solution?

- **A.** \([\text{A}^-] > [\text{HA}] > [\text{H}_3\text{O}^+] > [\text{OH}^-]\)
- **B.** \([\text{A}^-] > [\text{HA}] > [\text{OH}^-] > [\text{H}_3\text{O}^+]\)
- **C.** \([\text{HA}] > [\text{H}_3\text{O}^+] > [\text{A}^-] > [\text{OH}^-]\)
- **D.** \([\text{HA}] > [\text{A}^-] > [\text{H}_3\text{O}^+] > [\text{OH}^-]\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/123782/*