Le Chatelier’s Principle

Topic Content:

Le Chatelier’s principle explains how pressure, temperature, and concentration affect a system in equilibrium. Le Chatelier’s principle states that if an external constraint such as a change in temperature, pressure, or concentration is imposed on a chemical system in equilibrium, the equilibrium will shift so as to annul or neutralize the constraint.

Application of Le Chatelier’s Principle to System at Equilibrium:

The factors affecting the equilibrium position are temperature, concentration, and pressure of the reactants and products. Catalyst does not change the position of equilibrium but it affects the reaction equally in both directions.

1. Effect of Temperature Change on Equilibrium:

If a chemical system is in equilibrium and the temperature is lowered, the equilibrium will shift in the direction of change to annul the cooling effect by releasing more heat according to Le Chatelier’s principle.

But if the temperature is raised, the equilibrium position will shift so as to neutralize the heating effect by absorbing more heat.

For example, in an endothermic reaction, increasing the temperature of