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title: "At a certain temperature \\(T\\), the standard Gibbs free energy change for the gas-phase reaction represented below is \\(\\Delta G^\\circ = -5.7\\text{ kJ/mol}_{\\text{rxn}}\\), and the equilibrium constant is \\(K_p = 10.0\\).  \\[ \\text{I}_2(g) + \\text{Cl}_2(g) \\rightleftharpoons 2\\,\\text{ICl}(g) \\]  A rigid reaction vessel at temperature \\(T\\) is filled with the gases such that the initial partial pressures are \\(P_{\\text{I}_2} = 0.20\\text{ atm}\\), \\(P_{\\text{Cl}_2} = 0.20\\text{ atm}\\), and \\(P_{\\text{ICl}} = 2.0\\text{ atm}\\). Which of the following correctly predicts the sign of the instantaneous Gibbs free energy change, \\(\\Delta G\\), for the forward reaction under these initial conditions and the direction the reaction will proceed to reach equilibrium?"
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url: "https://nerd-notes.com/ubq/123926/"
date_modified: "2026-09-28T12:32:14+00:00"
---

# At a certain temperature \(T\), the standard Gibbs free energy change for the gas-phase reaction represented below is \(\Delta G^\circ = -5.7\text{ kJ/mol}_{\text{rxn}}\), and the equilibrium constant is \(K_p = 10.0\).

\[ \text{I}_2(g) + \text{Cl}_2(g) \rightleftharpoons 2\,\text{ICl}(g) \]

A rigid reaction vessel at temperature \(T\) is filled with the gases such that the initial partial pressures are \(P_{\text{I}_2} = 0.20\text{ atm}\), \(P_{\text{Cl}_2} = 0.20\text{ atm}\), and \(P_{\text{ICl}} = 2.0\text{ atm}\). Which of the following correctly predicts the sign of the instantaneous Gibbs free energy change, \(\Delta G\), for the forward reaction under these initial conditions and the direction the reaction will proceed to reach equilibrium?

At a certain temperature \(T\), the standard Gibbs free energy change for the gas-phase reaction represented below is \(\Delta G^\circ = -5.7\text{ kJ/mol}_{\text{rxn}}\), and the equilibrium constant is \(K_p = 10.0\).

\[ \text{I}_2(g) + \text{Cl}_2(g) \rightleftharpoons 2\,\text{ICl}(g) \]

A rigid reaction vessel at temperature \(T\) is filled with the gases such that the initial partial pressures are \(P_{\text{I}_2} = 0.20\text{ atm}\), \(P_{\text{Cl}_2} = 0.20\text{ atm}\), and \(P_{\text{ICl}} = 2.0\text{ atm}\). Which of the following correctly predicts the sign of the instantaneous Gibbs free energy change, \(\Delta G\), for the forward reaction under these initial conditions and the direction the reaction will proceed to reach equilibrium?

- **A.** \(\Delta G < 0\), and the reaction proceeds in the forward direction because \(\Delta G^\circ < 0\), which indicates that the formation of products is thermodynamically favored under all conditions.
- **B.** \(\Delta G < 0\), and the reaction proceeds in the reverse direction because the high initial partial pressure of \(\text{ICl}(g)\) drives the reaction toward reactants while maintaining a negative \(\Delta G\) for the forward process.
- **C.** \(\Delta G > 0\), and the reaction proceeds in the reverse direction because \(Q_p > K_p\), which makes the forward reaction thermodynamically unfavored under these nonstandard conditions.
- **D.** \(\Delta G > 0\), and the reaction proceeds in the forward direction because the system must form additional products to overcome the positive free energy barrier.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/123926/*