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title: "A student prepares an aqueous mixture containing both \\(0.10\\text{ M }\\text{HNO}_2\\text{(aq)}\\) and \\(0.10\\text{ M }\\text{HClO(aq)}\\) at \\(25^\\circ\\text{C}\\). The chemical equations and acid-ionization constants for the two weak acids are given below:  \\[ \\text{HNO}_2\\text{(aq)} + \\text{H}_2\\text{O(l)} \\rightleftharpoons \\text{H}_3\\text{O}^+\\text{(aq)} + \\text{NO}_2^-\\text{(aq)} \\quad K_a = 4.0 \\times 10^{-4} \\] \\[ \\text{HClO(aq)} + \\text{H}_2\\text{O(l)} \\rightleftharpoons \\text{H}_3\\text{O}^+\\text{(aq)} + \\text{ClO}^-\\text{(aq)} \\quad K_a = 3.0 \\times 10^{-8} \\]  Which of the following correctly predicts how the percent ionization of \\(\\text{HClO}\\) in this mixture compares to its percent ionization in a pure \\(0.10\\text{ M }\\text{HClO(aq)}\\) solution, and provides the correct justification?"
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url: "https://nerd-notes.com/ubq/123848/"
date_modified: "2026-09-28T12:30:32+00:00"
---

# A student prepares an aqueous mixture containing both \(0.10\text{ M }\text{HNO}_2\text{(aq)}\) and \(0.10\text{ M }\text{HClO(aq)}\) at \(25^\circ\text{C}\). The chemical equations and acid-ionization constants for the two weak acids are given below:

\[ \text{HNO}_2\text{(aq)} + \text{H}_2\text{O(l)} \rightleftharpoons \text{H}_3\text{O}^+\text{(aq)} + \text{NO}_2^-\text{(aq)} \quad K_a = 4.0 \times 10^{-4} \]
\[ \text{HClO(aq)} + \text{H}_2\text{O(l)} \rightleftharpoons \text{H}_3\text{O}^+\text{(aq)} + \text{ClO}^-\text{(aq)} \quad K_a = 3.0 \times 10^{-8} \]

Which of the following correctly predicts how the percent ionization of \(\text{HClO}\) in this mixture compares to its percent ionization in a pure \(0.10\text{ M }\text{HClO(aq)}\) solution, and provides the correct justification?

A student prepares an aqueous mixture containing both \(0.10\text{ M }\text{HNO}_2\text{(aq)}\) and \(0.10\text{ M }\text{HClO(aq)}\) at \(25^\circ\text{C}\). The chemical equations and acid-ionization constants for the two weak acids are given below:

\[ \text{HNO}_2\text{(aq)} + \text{H}_2\text{O(l)} \rightleftharpoons \text{H}_3\text{O}^+\text{(aq)} + \text{NO}_2^-\text{(aq)} \quad K_a = 4.0 \times 10^{-4} \]
\[ \text{HClO(aq)} + \text{H}_2\text{O(l)} \rightleftharpoons \text{H}_3\text{O}^+\text{(aq)} + \text{ClO}^-\text{(aq)} \quad K_a = 3.0 \times 10^{-8} \]

Which of the following correctly predicts how the percent ionization of \(\text{HClO}\) in this mixture compares to its percent ionization in a pure \(0.10\text{ M }\text{HClO(aq)}\) solution, and provides the correct justification?

- **A.** The percent ionization of \(\text{HClO}\) is greater in the mixture, because \(\text{NO}_2^-\text{(aq)}\) acts as a conjugate base that removes protons from \(\text{HClO(aq)}\), driving its ionization forward.
- **B.** The percent ionization of \(\text{HClO}\) is the same in the mixture, because the acid-ionization constant \(K_a\) of \(\text{HClO}\) is a thermodynamic constant at \(25^\circ\text{C}\) and is independent of the presence of other solutes.
- **C.** The percent ionization of \(\text{HClO}\) is less in the mixture, because \(\text{H}_3\text{O}^+\text{(aq)}\) generated predominantly by the ionization of \(\text{HNO}_2\text{(aq)}\) shifts the ionization equilibrium of \(\text{HClO}\) toward the reactants.
- **D.** The percent ionization of \(\text{HClO}\) is less in the mixture, because \(\text{HNO}_2\text{(aq)}\) is a stronger acid and completely ionizes in solution, consuming the available water molecules needed to hydrate \(\text{HClO(aq)}\).

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/123848/*