What is the Difference Between Homogeneous and Heterogeneous Equilibrium?

The difference between homogeneous and heterogeneous equilibrium lies in the phase of the reactants and products involved in the chemical reaction.

• Homogeneous Equilibrium: In a homogeneous equilibrium, all species (reactants and products) are present in the same phase. Common examples include gas-phase or solution reactions. For instance, consider the following reaction: $$2SO{2(g)} + O{2(g)} \rightleftharpoons 2SO_{3(g)}$$. In this case, all the reactants and products are in the gas phase.
• Heterogeneous Equilibrium: In a heterogeneous equilibrium, the species involved in the reaction exist in more than one phase, such as reactions involving solids and gases, or solids and liquids. An example of a heterogeneous equilibrium is the equilibrium established when steam is in contact with solid calcium carbonate, resulting in the formation of solid calcium oxide and gaseous carbon dioxide.

In summary, the main difference between homogeneous and heterogeneous equilibrium is the phase of the reactants and products involved in the reaction: homogeneous equilibrium involves species in the same phase, while heterogeneous equilibrium involves species in different phases.

Comparative Table: Homogeneous vs Heterogeneous Equilibrium

Here is a table comparing homogeneous and heterogeneous equilibria:

In summary, homogeneous equilibrium occurs when all reactants and products are in the same phase of matter, while heterogeneous equilibrium involves different phases. The equilibrium constant for homogeneous equilibria includes all reactant and product concentrations, whereas for heterogeneous equilibria, it must exclude the concentrations of solids and pure liquids.