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Difficulty: HardReversible Reactions and Dynamic Equilibrium

For the endothermic gaseous reaction N2O4(g)⇌2NO2(g)\text{N}_2\text{O}_4(g) \rightleftharpoons 2\text{NO}_2(g) at dynamic equilibrium in a closed vessel, decreasing the container volume at constant temperature increases the equilibrium constant KcK_c because the system shifts toward the side with fewer moles of gas.

Answer: Answer

Answer

The statement is False. Changing the container volume or pressure alters the equilibrium position (partial pressures/concentrations of species), but the equilibrium constant KcK_c is solely dependent on temperature.
The assertion is false because temperature is the only parameter capable of changing the value of the equilibrium constant KcK_c. Adjusting container volume alters total system pressure, which causes a shift in the position of equilibrium to re-establish the same KcK_c value.

Step-by-Step Solution

1
Analyze the impact of volume reduction on pressure and equilibrium position
Decreasing container volume increases the concentration and partial pressure of all gaseous species, causing a shift toward the side with fewer moles of gas (left side, 1 mole of N2O4\text{N}_2\text{O}_4 vs 2 moles of NO2\text{NO}_2).
Le Chatelier's principle dictates that a system at equilibrium will counteract an applied stress (increased pressure).
2
Determine the effect of volume/pressure changes on the equilibrium constant KcK_c
The equilibrium constant KcK_c remains unchanged.
The equilibrium constant KcK_c is a thermodynamic property defined by temperature alone. Changes in pressure or volume shift reactant/product ratios back to the exact ratio satisfying the same KcK_c value.

Key Concept

Independence of Equilibrium Constant (KcK_c) from Pressure and Volume Changes
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Topics

Reversible Reactions and Dynamic Equilibrium