Chemical equilibrium are important in the numerous biological and environmental processes, For example equilibria involving O2 molecules and the protein hemoglobin play a crucial role in the transport and delivery of O2 from our lungs to our muscles. Similar equilibria involving CO molecules and hemoglobin account for the toxicity of CO.
When a liquid evaporates in a closed container, molecules with relativity higher kinetic energy escape the liquid surface into the vapor phase strike the liquid molecules from the vapor phase strike the liquid surface and are retained in the liquid phase. It gives rise to a constant vapored pressure because of an equilibrium state at this stage. However, this is not static equilibrium and there is a lot of activity at the boundary between the liquid and the vapor. Thus, at equilibrium, the rate of evaporation is equal to the rate of condensation. It may be represented by H2 O (I)⇄ H2O 🌊
The double half arrows indicate that the processes in both the directions are going on simultaneously. The mixture of reactants and products in the equilibrium state is called an equilibrium mixture.
Equilibrium can be established for both physical processes and chemical reactions. The reaction may be fast or slow depending on the experimental conditions and the at a particular temperature react to gives products, the concentration of the reactions. When the reactions in a closed vessel at a particular temperature react to gives products, the concertation of the reaction, those of products keep on increasing for some time after which three react or products.
