Question

A gaseous system contains \( H_1 \), \( H_2 \), and \( I_2 \) which participate in the gas phase reaction: \[ 2H_1 \rightleftharpoons H_2 + I_2 \] At a state of reaction equilibrium, the number of thermodynamic degrees of freedom is:

• A. 1
• B. 2
• C. 3
• D. 4

Hint:

The degrees of freedom in a system indicate the number of independent variables that can be controlled without affecting others.

Answer 1

The Correct Option is B

Step 1: Use the Gibbs phase rule.
The number of degrees of freedom at equilibrium is given by the Gibbs phase rule: \[ F = C - P + 2 \] Where \( C \) is the number of components, and \( P \) is the number of phases. For this system, \( C = 3 \) and \( P = 1 \), so: \[ F = 3 - 1 + 2 = 2 \]

Step 2: Conclusion.
Thus, the correct number of thermodynamic degrees of freedom is (B) 2.