---
title: "The potential energy profile for the exothermic reaction \\(\\text{X(g)} \\rightarrow \\text{Y(g)}\\) in the presence and absence of a catalyst is shown in the diagram. Which of the following statements correctly describes the effect of adding the catalyst to the reaction mixture, and provides the 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/119715/"
date_modified: "2026-08-21T08:12:08+00:00"
---

# The potential energy profile for the exothermic reaction \(\text{X(g)} \rightarrow \text{Y(g)}\) in the presence and absence of a catalyst is shown in the diagram. Which of the following statements correctly describes the effect of adding the catalyst to the reaction mixture, and provides the correct justification?

The potential energy profile for the exothermic reaction \(\text{X(g)} \rightarrow \text{Y(g)}\) in the presence and absence of a catalyst is shown in the diagram. Which of the following statements correctly describes the effect of adding the catalyst to the reaction mixture, and provides the correct justification?

![A reaction energy profile graph with potential energy on the vertical axis and reaction coordinate on the horizontal axis. No numerical gridlines appear. The reactants start at a baseline potential energy on the left, and the products end at a lower potential energy on the right. Two curves connect reactants to products. Curve 1 is a solid line that rises to a high potential energy peak representing the uncatalyzed transition state before descending to the products. Curve 2 is a dashed line that begins at the exact same reactant energy level, rises to a noticeably lower potential energy peak representing the catalyzed pathway, and ends at the exact same product energy level. A legend at the top right indicates that the solid line represents the uncatalyzed reaction and the dashed line represents the catalyzed reaction. No other curves, labels, text, or annotations appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1787299927-WBCFDi.jpg)

- **A.** The reaction rate increases and \(\Delta H\) becomes more negative because the catalyst stabilizes the products relative to the reactants.
- **B.** The reaction rate increases and \(\Delta H\) becomes more negative because the catalyst lowers the potential energy of both the transition state and the products.
- **C.** The reaction rate increases and \(\Delta H\) remains unchanged because the catalyst provides an alternative mechanism with a lower activation energy without altering the potential energy of the reactants or products.
- **D.** The reaction rate increases and \(\Delta H\) remains unchanged because the catalyst increases the average kinetic energy of the reacting particles without altering the reaction pathway.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119715/*