It states that when a stress is applied to a system in equilibrium, the equilibrium will shift in such a manner as to relieve or neutralize the stress.
A. Collision Theory
B. Law of Mass Action
C. Principle of Le Chatlier
D. Ionic Theory
The correct answer and explanation is :
The correct answer is C. Principle of Le Chatelier.
Explanation:
Le Chatelier’s Principle is a fundamental concept in chemistry that explains how a system at equilibrium responds to external stresses. The principle states that if a stress (such as a change in concentration, temperature, or pressure) is applied to a system in equilibrium, the system will shift its position in a way that opposes the applied stress. This means that the system will attempt to counteract or neutralize the effect of the stress to restore a new equilibrium.
The principle is named after the French chemist Henri Le Chatelier, who formulated it in the 19th century. It applies to chemical reactions in dynamic equilibrium, where the rates of the forward and reverse reactions are equal, resulting in no net change in the concentrations of reactants and products.
Types of Stresses:
- Change in Concentration:
- If the concentration of one of the reactants or products is increased, the system will shift in a direction that consumes the added substance. For example, if more reactant is added, the system will favor the forward reaction to produce more products.
- Conversely, if a substance is removed, the system will shift to replace it.
- Change in Temperature:
- For exothermic reactions (which release heat), an increase in temperature will shift the equilibrium to the left (favoring the reverse reaction), as the system tries to absorb the added heat.
- For endothermic reactions (which absorb heat), increasing the temperature shifts the equilibrium to the right, favoring the forward reaction.
- Change in Pressure:
- In reactions involving gases, increasing pressure typically shifts the equilibrium toward the side with fewer moles of gas. This occurs because the system will try to reduce the pressure by favoring the side that has fewer molecules.
Le Chatelier’s principle provides a qualitative understanding of how equilibria respond to changes, and it helps in predicting the effects of various factors on the system’s equilibrium.
Other Choices:
- A. Collision Theory explains how chemical reactions occur and how reaction rates are influenced by factors like temperature and concentration but is unrelated to equilibrium.
- B. Law of Mass Action relates to the mathematical relationship between concentrations of reactants and products at equilibrium.
- D. Ionic Theory deals with the dissociation of ionic compounds in solution, not with equilibrium shifts.