Why does the rate or backward reaction increase with time?

The rate of a backward reaction increases with time primarily due to the accumulation of products, which can then collide with reactants more frequently. As the concentration of products rises, the likelihood of effective collisions between reactants and products increases, leading to a higher rate of the reverse reaction. Additionally, as the system approaches equilibrium, the dynamic balance between the forward and backward reactions can shift, enhancing the rate of the backward reaction.