The acid-base chemical reaction that is irreversible among the options provided is:
strong acid added to water.
When a strong acid, like hydrochloric acid (HCl), is added to water, it completely dissociates into its ions (H⁺ and Cl⁻), and this reaction does not reverse under normal conditions. In contrast, weak acids and bases only partially dissociate in water, making their reactions more reversible.