What is the difference between a weak acid and a strong acid?

The distinction between a weak acid and a strong acid fundamentally lies in the amount of hydrogen ions released into a solution. A strong acid is characterized by its complete dissociation in water, meaning it releases a significant number of hydrogen ions, resulting in a high concentration of hydronium ions (H3O+). This complete ionization makes strong acids very effective at conducting electricity and reacting with bases.

Conversely, weak acids only partially dissociate in water. This means that even when they are dissolved, a smaller portion of the acid molecules will lose protons, leading to a lower concentration of hydrogen ions compared to strong acids. This partial dissociation is responsible for the weaker acidity and comparatively less reactivity of weak acids in various chemical reactions.

Temperature, viscosity, and molecular weight do play roles in the behavior of acids but do not define their classification as strong or weak. These properties can affect how acids function or behave in different environments, but they are not the criteria for determining the strength of an acid. The correct answer reflects the essential concept of ionization as the key factor distinguishing weak acids from strong acids.