Equilibrium is a steady state,but it is dynamic in nature. What is the meaning of this statement?

One mole of $A_{(g)}$ is heated to $200^{\circ} C$ in a one litre closed flask,until the following equilibrium is reached:
$A_{(g)} \rightleftharpoons B_{(g)}$
The rate of forward reaction at equilibrium is $0.02 \ mol \ L^{-1} \ min^{-1}$. What is the rate (in $mol \ L^{-1} \ min^{-1}$) of the backward reaction at equilibrium?

Predict which of the following reactions will have an appreciable concentration of both reactants and products:
$(a)$ $Cl_{2(g)} \longleftrightarrow 2Cl_{(g)};$ $K_{c}=5 \times 10^{-39}$
$(b)$ $Cl_{2(g)}+2NO_{(g)} \longleftrightarrow 2NOCl_{(g)};$ $K_{c}=3.7 \times 10^{8}$
$(c)$ $Cl_{2(g)}+2NO_{2(g)} \longleftrightarrow 2NO_{2}Cl_{(g)};$ $K_{c}=1.8$

In a reversible reaction $A \overset{k_1}{\underset{k_2}{\longleftrightarrow}} B$,the initial concentrations of $A$ and $B$ are $a$ and $b$,and the equilibrium concentrations are $(a - x)$ and $(b + x)$ respectively. Express $x$ in terms of $k_1, k_2, a$,and $b$.

Write the general characteristics of equilibria involving physical processes.

Explain the dynamic nature of chemical equilibrium with a suitable reaction example.