Do all chemical reactions end?

The statement that some chemical reactions are reversible is accurate, which makes this answer the correct choice. In chemistry, a reversible reaction is one in which the products can react to form the original reactants again. This dynamic process means that the reaction does not have a definitive endpoint; instead, it can establish an equilibrium where the rate of the forward reaction is equal to the rate of the reverse reaction, allowing both the reactants and products to coexist.

In contrast, some reactions are irreversible, meaning once the reactants are transformed into products, they cannot revert back under normal conditions. This distinction underlines how not all reactions have an endpoint.

The other options are not correct because they either generalize all reactions or inaccurately categorize reaction types in terms of thermodynamics without focusing on reversibility. By understanding that some reactions can go in both directions, it becomes clear why the assertion about reversible reactions being part of chemical processes is significant.