Question

State the Le Chatelier's principle.

Answer 1

Le Chatelier's Principle, which is also known as the Chatelier's principle and " The Equilibrium Law ", is a law that is used to predict the effect of different types of change in conditions on the chemical equilibria. This principle is named the French chemist Henry Louise Le Chatelier.
Complete answer step by step:

• Le Chatelier's principle is stated as follows:
  " When any system at equilibrium for a long period of time is subjected to a change in concentration, temperature, volume, or pressure,
  (1) the system changes to a new equilibrium, and
  (2) this change partly counteracts the applied change."
• He said that the equilibrium adjusts the forward and the backward reactions so as to accept the changes that are affecting the equilibrium conditions.
• The conditions that affect the equilibrium are:

1. Effect of concentration changes: According to the principle, if the concentration of the reactants is increased then equilibrium will shift towards the use of the reactants which will decrease the concentration of the reactants and thus increase the concentration of the product. Similarly, if we increase the concentration of the products in the reaction the equilibrium will increase the backward reaction to decrease the concentration of the products.
2. Effect of change of volume and pressure: There is no effect in the reactions of liquid or solids due to the change in volume, pressure, or inert gas. However, they may affect the gaseous solution if only when the difference in the sum of the number of reactant and product molecules $(\delta n)$is not zero. If $(\delta n > 0)$, then an increase in pressure or decrease in volume will increase the backward reaction and vice-versa. But, if $(\delta n < 0)$ then an increase in pressure or decrease in volume will increase the forward reaction.
3. Effect of change of temperature: According to this principle, in an endothermic reaction, if we increase the temperature, then the equilibrium shifts towards the forward reaction and vice versa. But, in an exothermic reaction, if we increase the temperature, then the equilibrium shifts towards the backward reaction and vice versa.

Note: Le Chatelier's principle is very important, particularly in industrial applications, where yields need to be accurately predicted and maximized. This principle is used in the synthesis of ammonia, sulphur trioxide, ozone, etc.