---
title: "The table below provides the acid-ionization constant, \\(K_a\\), and bond enthalpy for two hydrogen halides at \\(298\\text{ K}\\).  | Hydrogen Halide | \\(K_a\\) at \\(298\\text{ K}\\) | \\(\\text{H}-\\text{X}\\) Bond Enthalpy (\\(\\text{kJ/mol}\\)) | | :— | :— | :— | | \\(\\text{HF}\\) | \\(6.3 \\times 10^{-4}\\) | \\(567\\) | | \\(\\text{HCl}\\) | \\(\\gg 1\\) | \\(431\\) |  Which of the following statements best compares the acid strength of \\(\\text{HF}\\) to that of \\(\\text{HCl}\\) and provides the correct justification?"
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url: "https://nerd-notes.com/ubq/119773/"
date_modified: "2026-08-21T08:12:18+00:00"
---

# The table below provides the acid-ionization constant, \(K_a\), and bond enthalpy for two hydrogen halides at \(298\text{ K}\).

| Hydrogen Halide | \(K_a\) at \(298\text{ K}\) | \(\text{H}-\text{X}\) Bond Enthalpy (\(\text{kJ/mol}\)) |
| :— | :— | :— |
| \(\text{HF}\) | \(6.3 \times 10^{-4}\) | \(567\) |
| \(\text{HCl}\) | \(\gg 1\) | \(431\) |

Which of the following statements best compares the acid strength of \(\text{HF}\) to that of \(\text{HCl}\) and provides the correct justification?

The table below provides the acid-ionization constant, \(K_a\), and bond enthalpy for two hydrogen halides at \(298\text{ K}\).

| Hydrogen Halide | \(K_a\) at \(298\text{ K}\) | \(\text{H}-\text{X}\) Bond Enthalpy (\(\text{kJ/mol}\)) |
| :--- | :--- | :--- |
| \(\text{HF}\) | \(6.3 \times 10^{-4}\) | \(567\) |
| \(\text{HCl}\) | \(\gg 1\) | \(431\) |

Which of the following statements best compares the acid strength of \(\text{HF}\) to that of \(\text{HCl}\) and provides the correct justification?

- **A.** \(\text{HF}\) is a weaker acid than \(\text{HCl}\) because the \(\text{H}-\text{F}\) bond has a higher bond enthalpy than the \(\text{H}-\text{Cl}\) bond, making proton transfer to water less energetically favorable.
- **B.** \(\text{HF}\) is a weaker acid than \(\text{HCl}\) because the \(\text{H}-\text{F}\) bond is less polar than the \(\text{H}-\text{Cl}\) bond, decreasing the electrostatic attraction between water molecules and the hydrogen atom.
- **C.** \(\text{HF}\) is a stronger acid than \(\text{HCl}\) because fluorine has a higher electronegativity than chlorine, which increases the polarity of the \(\text{H}-\text{F}\) bond and facilitates complete ionization.
- **D.** \(\text{HF}\) is a stronger acid than \(\text{HCl}\) because the smaller ionic radius of \(\text{F}^-\) concentrates negative charge, stabilizing the conjugate base more effectively in aqueous solution.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119773/*