What distinguishes strong acids from weak acids?

The correct answer highlights the fundamental difference in how strong acids and weak acids behave in solution, specifically regarding their dissociation. Strong acids are characterized by their ability to completely dissociate into ions when dissolved in water, which means that they release all of their hydrogen ions (H⁺) into the solution. This results in a high concentration of hydrogen ions, leading to a lower pH and a highly acidic solution.

On the other hand, weak acids do not dissociate completely; instead, they only partially release hydrogen ions. This means that in a solution of a weak acid, there are both undissociated acid molecules and hydrogen ions present. The extent of dissociation for weak acids is controlled by their acid dissociation constant (Ka), and the resulting solution has a higher pH compared to a strong acid at the same concentration.

Understanding this difference is crucial in predicting the behavior of acids in various chemical reactions and in practical applications such as titrations, buffer solutions, and acid-base reactions. The concept of complete versus partial dissociation serves as the basis for distinguishing strong from weak acids effectively.