Equilibrium
Equilibrium is a state where the forward and reverse reactions occur at the same rate, resulting in a constant concentration of reactants and products. In the context of chemistry, equilibrium can be classified into two types: physical equilibrium and chemical equilibrium.

Physical Equilibrium
- Physical equilibrium occurs when the physical state of a substance changes without any change in its chemical composition.
- An example of physical equilibrium is the equilibrium between ice and water at 0°C.

Chemical Equilibrium
- Chemical equilibrium occurs when the rate of the forward reaction is equal to the rate of the reverse reaction.
- In a chemical equilibrium, the concentrations of reactants and products remain constant over time.
- The equilibrium constant (Kc) is a measure of the extent of a chemical reaction at equilibrium.

JEE Important Questions on Equilibrium
1. What is the difference between physical equilibrium and chemical equilibrium?
2. How does the equilibrium constant (Kc) relate to the concentrations of reactants and products in a chemical equilibrium?
3. Explain Le Chatelier's principle and how it can be used to predict the effect of changing conditions on a system at equilibrium.
4. Calculate the equilibrium constant for the reaction: 2A + 3B ⇌ 4C, given the initial concentrations of A, B, and C.
5. Discuss the factors that can affect the position of equilibrium in a chemical reaction.
By understanding the concept of equilibrium and practicing related JEE questions, you can enhance your problem-solving skills and excel in your JEE Main exam.