Question

Identify the Boudouard equilibrium reaction from the following:

• A. \( \text{C} + \text{O}_2 \rightarrow \text{CO}_2 \)
• B. \( 2\text{C} + \text{O}_2 \rightarrow 2\text{CO} \)
• C. \( \text{Fe} + \text{CO}_2 \leftrightarrow \text{FeO} + \text{CO} \)
• D. \( \text{CO}_2 + \text{C} \leftrightarrow 2\text{CO} \)

Hint:

The Boudouard reaction (\( \text{CO}_2 + \text{C} \leftrightarrow 2\text{CO} \)) is a fundamental concept in extractive metallurgy. Memorize its form and its temperature dependence: high temperature favors CO, low temperature favors CO\(_2\).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The Boudouard reaction is a named chemical equilibrium that is critically important in high-temperature metallurgical processes involving carbon, such as blast furnaces and gasifiers. It describes the equilibrium between carbon dioxide (CO\(_2\)), solid carbon (C), and carbon monoxide (CO).

Step 3: Detailed Explanation:
The equilibrium is written as: \[ \text{CO}_2(g) + \text{C}(s) \leftrightarrow 2\text{CO}(g) \] This reaction is highly temperature-dependent.

• At high temperatures (above approximately 700°C), the equilibrium shifts to the right, favoring the formation of carbon monoxide (CO). This is why CO is the dominant carbon oxide in the high-temperature zones of a blast furnace. The reaction is endothermic.

• At lower temperatures (below 700°C), the equilibrium shifts to the left, favoring the formation of carbon dioxide (CO\(_2\)) and carbon (C).
Let's analyze the options:

• (A) is the complete combustion of carbon.

• (B) is the incomplete combustion of carbon.

• (C) is the equilibrium for the oxidation/reduction of iron by CO/CO\(_2\).

• (D) is the precise representation of the Boudouard reaction.

Step 4: Final Answer:
The Boudouard equilibrium reaction is correctly identified as \( \text{CO}_2 + \text{C} \leftrightarrow 2\text{CO} \).