Chemical Equilibrium

Chemical equilibrium is a state in which the rates of forward and reverse reactions in a chemical system are equal, resulting in a constant concentration of reactants and products.

Example:

The reaction between nitrogen gas (N₂) and hydrogen gas (H₂) to form ammonia (NH₃) exhibits chemical equilibrium:
N₂ + 3H₂ ⇌ 2NH₃
The dissociation of hydrogen iodide (HI) into hydrogen (H₂) and iodine (I₂) is another example of chemical equilibrium:
2HI ⇌ H₂ + I₂

Reversible Equilibrium:

Reversible equilibrium refers to a state in which a chemical reaction can proceed in both the forward and reverse directions. It occurs when the rates of the forward and reverse reactions are equal.

Formula:

aA + bB ⇌ cC + dD

Example:

Consider the reaction between nitrogen gas (N₂) and hydrogen gas (H₂) to form ammonia (NH₃):

N₂ + 3H₂ ⇌ 2NH₃

Dynamic Equilibrium:

Dynamic equilibrium describes a situation in which the concentrations of reactants and products remain constant over time, while the individual molecular-level processes continue to occur. It is characterized by a balance between forward and reverse reactions.

Example:

Consider the dissociation of hydrogen iodide (HI) into hydrogen (H₂) and iodine (I₂) is another example of chemical equilibrium:

2HI ⇌ H₂ + I₂

Macroscopic Characteristics of Forward and Reverse in Reversible Equilibrium:

In a reversible equilibrium, the forward and reverse reactions exhibit the following macroscopic characteristics:

Forward Reaction:

The forward reaction proceeds from reactants to products.
The concentration of reactants gradually decreases over time.
The concentration of products increases as the reaction progresses.

Reverse Reaction:

The reverse reaction proceeds from products to reactants.
The concentration of products gradually decreases over time.
The concentration of reactants increases as the reaction proceeds.

Macroscopic Characteristics of Forward and Reverse in Dynamic Equilibrium:

In a dynamic equilibrium, the forward and reverse processes exhibit the following macroscopic characteristics:

Forward Process:

The forward process involves the conversion of reactants into products.
The concentration of reactants decreases as the forward process occurs.
The concentration of products increases as the forward process takes place.

Reverse Process:

The reverse process involves the conversion of products back into reactants.
The concentration of products decreases as the reverse process occurs.
The concentration of reactants increases as the reverse process takes place.