Question

I: After a system has reacted chemical equilibrium, there is no change in the concentrations of reactants and products.
II: Reactions are not reversible at equilibrium.

Answer 1

After a system has reached chemical equilibrium, the rates of forward and backward reaction become equal. The concentrations of different products and reactants becomes constant. At equilibrium, the reactions are of reversible nature. It continues in the forward and backward directions at equal rates. So, the equilibrium attained is dynamic in nature.