---
title: "The potential energy profile for an exothermic gaseous reaction is shown in the diagram below.  \\[ \\text{X}_2\\text{(g)} + \\text{Y}_2\\text{(g)} \\rightarrow 2\\text{XY(g)} \\]  A student proposes adding a suitable catalyst to increase the rate of formation of \\(\\text{XY(g)}\\). Which of the following correctly predicts the effect of the catalyst on the activation energy of the reverse reaction, \\(E_{a,\\text{rev}}\\), and the overall enthalpy change of the reaction, \\(\\Delta H\\)?"
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url: "https://nerd-notes.com/ubq/121431/"
date_modified: "2026-08-23T05:02:19+00:00"
---

# The potential energy profile for an exothermic gaseous reaction is shown in the diagram below.

\[ \text{X}_2\text{(g)} + \text{Y}_2\text{(g)} \rightarrow 2\text{XY(g)} \]

A student proposes adding a suitable catalyst to increase the rate of formation of \(\text{XY(g)}\). Which of the following correctly predicts the effect of the catalyst on the activation energy of the reverse reaction, \(E_{a,\text{rev}}\), and the overall enthalpy change of the reaction, \(\Delta H\)?

The potential energy profile for an exothermic gaseous reaction is shown in the diagram below.

\[ \text{X}_2\text{(g)} + \text{Y}_2\text{(g)} \rightarrow 2\text{XY(g)} \]

A student proposes adding a suitable catalyst to increase the rate of formation of \(\text{XY(g)}\). Which of the following correctly predicts the effect of the catalyst on the activation energy of the reverse reaction, \(E_{a,\text{rev}}\), and the overall enthalpy change of the reaction, \(\Delta H\)?

![A grayscale potential energy profile on bare axes with no gridlines. The vertical axis is labeled Potential Energy and the horizontal axis is labeled Reaction Progress. On the left, a flat horizontal plateau is labeled with text X2 + Y2. On the right, a lower flat horizontal plateau is labeled with text 2XY. A solid line represents the uncatalyzed pathway, starting at the reactants plateau, rising smoothly to a single tall peak, and descending to the products plateau. A dashed line represents the catalyzed pathway, starting at the exact same reactants plateau, rising to a first peak distinctly lower than the uncatalyzed peak, dipping into a shallow local minimum, rising to a second low peak, and descending to the exact same products plateau. A text legend indicates solid line as Uncatalyzed and dashed line as Catalyzed. No other particles, labels, text, or annotations appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1787461339-qGYAwd.jpg)

- **A.** The value of \(E_{a,\text{rev}}\) decreases, and \(\Delta H\) becomes more negative.
- **B.** The value of \(E_{a,\text{rev}}\) remains unchanged, and \(\Delta H\) remains unchanged.
- **C.** The value of \(E_{a,\text{rev}}\) decreases, and \(\Delta H\) remains unchanged.
- **D.** The value of \(E_{a,\text{rev}}\) increases, and \(\Delta H\) becomes less negative.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/121431/*