Test: Dynamic Equilibrium (July 12) - NEET MCQ

• It is dynamic because it never stops it keeps going even if try to disturb it the equilibrium will adjust itself such as to maintain its state.
• It can be achieved in physical reactions like ice and water or in chemical reactions too.
• It can only be achieved in a closed system because if the system would be open the reactants or products may escape from the system.

Therefore, equilibrium cannot be established.

The equilibrium state can only be reached if the chemical reaction takes place in a closed system. Otherwise, some of the products may escape, leading to the absence of a reverse reaction.

• Bronsted–Lowry theory, also called proton theory of acids and bases, a theory, introduced independently in 1923 by the Danish chemist Johannes Nicolaus Bronsted and the English chemist Thomas Martin Lowry, stating that any compound that can transfer a proton to any other compound is an acid, and the compound that accepts the proton is a base.
• A proton is a nuclear particle with a unit positive electrical charge; it is represented by the symbol H+ because it constitutes the nucleus of a hydrogen atom.

An understanding of equilibrium is important in the chemical industry. Equilibrium reactions are involved in some of the stages in the large-scale production of ammonia, sulfuric acid and many other chemicals. 

Silver chloride forms a soluble complex with aqueous ammonia.
AgCl + 2NH₃→ [Ag(NH₃)₂]Cl

The rate of conversion of physical quantity becomes constant both in backward and forward direction so,it seems to be stopped but in actually rate of backward and rate of forward reaction are same.

When rate of forward reaction is equal to the rate of backward reaction then equilibrium is supposed to be established.

The Haber Process combines nitrogen from the air with hydrogen derived mainly from natural gas (methane) into ammonia. The reaction is reversible and the production of ammonia is exothermic.
At each pass of the gases through the reactor, only about 15% of the nitrogen and hydrogen converts to ammonia. By continual recycling of the unreacted nitrogen and hydrogen, the overall conversion is about 98%.

Reversible Reaction

• The common observation for any reactions when they are reacted in closed containers would not go to completion, for some given conditions like temperature and pressure.
• For all those cases, only the reactants are found to be present in the intial stages, but with the progress of reaction, the reactants concentration decreases and to that of the products increases.
• A stage is finally reached where there is no more change of reactants and products concentration is observed.
• The state where the reactants and products concentrations do not show any visible change within a given period of time is better known as the state of chemical equilibrium. 
• The reactant amount that remains unused depends upon the experimental conditions like concentration of components, temperature of the system, pressure of the system and the reaction nature.

Law of mass action states that the rate of reaction is proportional to the product of molar concentration of reactant with each concentration term raised to power its stoichiometric coefficient.