The equilibria involving physical processes can only be achieved when the change occurring is only a type of physical change and not a chemical change

• When gases are being involved in the process then (i) Equilibrium is possible only in a closed system at a given temperature satisfies the equilibria of physical processes because if the system (the vessel) is open then some gases will be escaping and there will be no Equilibrium.

• Again, in the process (ii) All measurable properties of the system remain constant satisfies the property of physical processes too because reaching the Equilibrium at constant temperature and at a closed system the observable properties will always remain constant.

• (iv) The opposing processes occur at the same rate and there is dynamic but stable condition also agrees with the conditions of Equilibrium of physical processes because the rate of the two oppositely directed processes i.e. the forward and backward process are occurring at same rate (reversibility) and therefore the nature of the Equilibrium will be dynamic but in a stable condition.

Reaching the Equilibrium, the rate of the forward and backward process i.e. two oppositely directed processes becomes equal, but that does not necessarily mean that the processes are stopped at either direction, instead there exists a condition which is dynamic in nature but is quite stable.