Question

Describe what dynamic equilibrium means, and also say how the equilibrium is represented by vapor pressure above a liquid?

Answer 1

Hint : To answer this question, we must be familiar with what equilibrium and dynamic equilibrium actually means. We know that when reactants and products are at the same concentration, it is in equilibrium. Check if the given system is open or closed. Depending on that, discuss the properties of dynamic equilibrium.

Complete Step By Step Answer:
We have learnt that when the concentration of both reactants and products turn out to be the same, the system is at equilibrium. Now consider dynamic equilibrium’s case:
- We must know that equilibrium becomes dynamic when the given reaction is one that is reversible. In that, the rate of both the reactions, forward and backward will be the same. Continuously the reaction can go forward and backward but as a whole, the total change is zero.
- The given scenario for vapor pressure of a liquid is one such example for a dynamic equilibrium.
Since certain particles will be able to exit the liquid phase and pass into the gas phase, the liquid will continue to lose particles to the air above as it is first deposited in the bottle.
Because of the added vapor pressure, particles in the gas phase would therefore return to the liquid phase.
The rate at which these gas particles return to the liquid (condensation) will eventually equal the rate at which the gas phase leaves the liquid (known as evaporation).
Dynamic equilibrium occurs when these rates are identical.

Note :
We have now discussed dynamic equilibrium, but equilibrium can be of two ways: static or dynamic. We will now see what is different among the two states of equilibriums:
For static equilibrium:
- When the reaction cannot be reversed, it is an irreversible reaction and this equilibrium happens only in such cases.
- It represents a state of rest.
- For open or closed systems this can occur.
- The reaction rates for forward and backward are both zero.
For dynamic equilibrium:
- When the reaction can be reversed this occurs.
- It is in motion, continues participation.
- Only when the system is closed.
- The reaction rates for forward and backward are both equal.