---
title: "A student investigates the reversible gas-phase synthesis of hydrogen iodide at a constant temperature of \\(700\\text{ K}\\), represented by the balanced equation below:  \\[ \\text{H}_2\\text{(g)} + \\text{I}_2\\text{(g)} \\rightleftharpoons 2\\,\\text{HI(g)} \\]  Which of the following is the correct equilibrium-constant expression, \\(K_c\\), for this reaction?"
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url: "https://nerd-notes.com/ubq/120008/"
date_modified: "2026-08-21T08:31:50+00:00"
---

# A student investigates the reversible gas-phase synthesis of hydrogen iodide at a constant temperature of \(700\text{ K}\), represented by the balanced equation below:

\[ \text{H}_2\text{(g)} + \text{I}_2\text{(g)} \rightleftharpoons 2\,\text{HI(g)} \]

Which of the following is the correct equilibrium-constant expression, \(K_c\), for this reaction?

A student investigates the reversible gas-phase synthesis of hydrogen iodide at a constant temperature of \(700\text{ K}\), represented by the balanced equation below:

\[ \text{H}_2\text{(g)} + \text{I}_2\text{(g)} \rightleftharpoons 2\,\text{HI(g)} \]

Which of the following is the correct equilibrium-constant expression, \(K_c\), for this reaction?

- **A.** \(K_c = \dfrac{[\text{H}_2][\text{I}_2]}{[\text{HI}]^2}\)
- **B.** \(K_c = \dfrac{2[\text{HI}]}{[\text{H}_2][\text{I}_2]}\)
- **C.** \(K_c = \dfrac{[\text{HI}]^2}{[\text{H}_2][\text{I}_2]}\)
- **D.** \(K_c = \dfrac{[\text{HI}]}{[\text{H}_2][\text{I}_2]}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/120008/*