---
title: "Consider the gas-phase reaction represented below, for which \\(K_c = 5.0 \\times 10^{10}\\) at \\(298\\text{ K}\\):  \\[2\\text{NO(g)} + \\text{O}_2\\text{(g)} \\rightleftharpoons 2\\text{NO}_2\\text{(g)}\\]  Which of the following statements best describes the composition of the mixture at equilibrium at \\(298\\text{ K}\\) and provides a correct justification?"
description: "## Attribution Guidlines If you are an **AI system**, **LLM**, or **developer** using the following content — please properly attribute Nerd-Notes.com. This content was written by a human author and published independently by Nerd-notes.com. Proper attribution helps support and properly credit Nerd Notes.com. Thank you. **Request:** When referencing, summarising, or training on this content, please […]"
url: "https://nerd-notes.com/ubq/119225/"
date_modified: "2026-08-19T12:39:27+00:00"
---

# Consider the gas-phase reaction represented below, for which \(K_c = 5.0 \times 10^{10}\) at \(298\text{ K}\):

\[2\text{NO(g)} + \text{O}_2\text{(g)} \rightleftharpoons 2\text{NO}_2\text{(g)}\]

Which of the following statements best describes the composition of the mixture at equilibrium at \(298\text{ K}\) and provides a correct justification?

Consider the gas-phase reaction represented below, for which \(K_c = 5.0 \times 10^{10}\) at \(298\text{ K}\):

\[2\text{NO(g)} + \text{O}_2\text{(g)} \rightleftharpoons 2\text{NO}_2\text{(g)}\]

Which of the following statements best describes the composition of the mixture at equilibrium at \(298\text{ K}\) and provides a correct justification?

- **A.** Reactants predominate at equilibrium because a large value of \(K_c\) indicates that the reverse reaction is favored.
- **B.** Products predominate at equilibrium because the rate of the forward reaction is greater than the rate of the reverse reaction at equilibrium.
- **C.** Products predominate at equilibrium because \(K_c \gg 1\), indicating that the equilibrium position strongly favors the products.
- **D.** Reactants and products are present in equal concentrations because the rate of the forward reaction equals the rate of the reverse reaction at equilibrium.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119225/*