Which is true of weak acids in terms of dissociation?

Weak acids are characterized by their partial dissociation in solution. Unlike strong acids, which completely ionize in water, weak acids only partially dissociate into their constituent ions. This means that when a weak acid is added to water, not all of the acid molecules break apart; instead, an equilibrium is established between the undissociated acid and the ions produced.

In the context of a weak acid, such as acetic acid (CH₃COOH), when it dissolves in water, only a fraction of the acetic acid molecules will donate protons (H⁺ ions), while the remainder will stay intact as undissociated molecules. This behavior is a fundamental characteristic of weak acids and is why they have specific pH levels that are higher than that of strong acids at the same concentration.

Understanding this property of weak acids is crucial for many applications in chemistry, including buffer solutions and equilibrium calculations, where the equilibrium constant can be used to describe the extent of dissociation.