Final answer:
The primary difference between a strong acid and a weak acid is the extent of ionization in solution.
Step-by-step explanation:
The primary difference between a strong acid and a weak acid is that a strong acid completely ionizes in solution, while a weak acid only partially ionizes. A strong acid like hydrochloric acid (HCl) will donate all of its protons to water, resulting in the formation of H+ ions and chloride ions. On the other hand, a weak acid like acetic acid (CH3COOH) will only donate a small fraction of its protons to water, resulting in the formation of H+ ions and acetate ions.