In a chemical reaction,equilibrium is established when:

In the reversible reaction,a catalyst is the substance which:

Chemical equilibrium is dynamic in nature because

Explain equilibrium in a saturated solution and its dynamic nature.

Among the following,the correct statement about the chemical equilibrium is

$A$ liquid is in equilibrium with its vapour in a sealed container at a fixed temperature. The volume of the container is suddenly increased.
$(a)$ What is the initial effect of the change on vapour pressure?
$(b)$ How do rates of evaporation and condensation change initially?
$(c)$ What happens when equilibrium is restored finally and what will be the final vapour pressure?