The modern interpretation of Le Châtelier's principle states that if a system at equilibrium, which occurs when the rate of the forward reaction equals the rate of the reverse reaction, is disturbed, the system will shift so as to relieve the disturbance. Thus, Le Châtelier's principle asserts that the equilibrium of a system can be changed by variations in temperature, pressure, volume, or in concentration of the reactants or products.

Henri Le Châtelier was a French chemist who became interested in the conditions needed for equilibrium in chemical reactions after examining some unexpected results at a mine's furnace. The reaction of iron oxides with carbon monoxide in the furnace was believed to produce iron and carbon dioxide. However, the gases emerging from the furnace contained a considerable amount of carbon monoxide. Le Châ...