What is meant by dynamic equilibrium?
Explain with suiitable examples.

Explanation

Dynamic equilibrium : The forward and reverse reactions of a reversible reaction continue to take place with equal rates simultaneously at the equililbrium stage also. Hence the equilibrium is called Dynamic equilibrium.
Explanation : In order to understand the dynamic nature of the reaction, synthesis of ammonia is carried with exactly the same starting conditions but using `D_(2)` (deuterium) in place of `H_(2)`. The reaction mixtures starting either with `H_(2)` or `D_(2)` reach equilibrium with the same composition, except that `D_(2) and ND_(3)` are present instead of `H_(2) and NH_(3)` . After equilibrium is attained, these two mixtures `(H_(2),N_(2),NH_(3) and D_(2), N_(2), ND_(3))` are mixed together and left for a while. Later when this mixture analysed, it is found that the concentration of ammonia is just the same as before. However, when this mixture is analysed by a moss spectrometer, it is found that ammonia and.all deuterium containing forms of ammonia `(NH_(3)NH_(2)D,NHD_(2) and ND_(3)`) and dihydrogen and its deutrated forms `(H_(4), HD and D_(2))` are present. Thus one can conclude that scrambling of H and D atoms.in the molecules must result from a contínuation of the forward and reverse reactions in the mixture. If the reaction had simply stopped when they reached equilibrium, then there would have been no mixing of isotopes in this way.
Use of isotope (deuterium). in the formation of ammonia clearly indicates that chemical reaction react a state of dynamic equilibriuốn in which the rates of forward and reverse reactions are equal and there is no net change in composition.