Final answer:
Weak acids and bases are highly reversible and this is true. They reach chemical equilibrium with both the forward and reverse reactions occurring simultaneously. Equilibrium arrows represent this reversibility and indicate the relative strength and concentration of the substances in the reaction.
Step-by-step explanation:
The statement that weak acids and bases are highly reversible and require an equilibrium arrow is true. Ionization of weak acids or bases are reversible reactions, where both the forward and reverse reactions reach a state known as chemical equilibrium. This state is represented using double arrows, as seen in the ionization reaction of the weak acid HC2H3O2 which can be written as:
HC2H3O2(aq) + H2O(l) ⇌ H3O+(aq) + C2H3O2-(aq)
In any Brønsted-Lowry acid-base reaction, it is generally true that a stronger acid and base will react to form a weaker acid and base. The direction of the acid-base equilibrium will favor the formation of the weaker acid and base, which will have the longer equilibrium arrow pointing towards them, indicating a higher concentration at equilibrium.
The key takeaway from this is that the equilibrium arrows not only show the reversibility of the reaction but also suggest the relative strengths of the acids and bases involved and their concentration in the equilibrium mixture.