Question

Which of the following is not a general characteristic of equilibrium involving physical processes?

Answer 1

(a) True
Equilibrium is possible only in a closed system at a given temperature.

(b) True
All measurable properties of a system remain constant

(c) False and (d) True

In a dynamic equilibrium, reactions continue to occur it does not get stop. It is just that the concentration of reactants and products are not changing with time and rate of forward reaction is equal to rate of backward.

Hence the incorrect option is C


Theory:

Physical Equilibrium:
If the opposing process in a reaction involves only physical change, the equilibrium is called physical equilibrium.
Three types of physical equilibrium :
1.Solid - liquid equilibrium
2.Liquid - gas equilibrium
3.Solid - gas equilibrium

Liq-vapour equilibrium :
Here the vapour and the liquid forms of a substance exist simultaneously at a characteristic
temperature called as boiling point and at 1 atm pressure.
For ex:
At ${100}^{\circ }C$ which is the boiling point of water and 1 atm pressure,
$Water\left(l\right)\rightleftharpoons Steam\left(g\right)$ both liquid water and water vapour (steam) exist simultaneously, provided the vapour does not escape.
Note :- Liquid vapour equilibrium can exist only in a closed system.


Evaporation vs Condensation
Evaporation is the process by which an element or compound transitions from its liquid state to its gaseous state below the temperature at which it boils.
Condensation is the process in which gas changes into a liquid when it touches a cooler surface.
For ex. Rate at which water molecules leave the wet towel which is in sunlight is not equal to the rate at which water vapour changes to liquid.
While in the case of wet towel in a closed container, then after some point of time , rate at which water molecules leave the towel becomes equal to rate at which vapour changes to liquid water
So for a closed system
$Water\left(l\right)\rightleftharpoons vapour\left(g\right)$