How can a strong acid be distinguished from a weak acid in solution?

A strong acid can be distinguished from a weak acid in solution primarily through its ionization behavior. A strong acid completely ionizes in water, meaning that it dissociates entirely into its constituent ions. For example, hydrochloric acid (HCl) dissociates fully into H⁺ and Cl⁻ ions when dissolved in water. This complete dissociation leads to a higher concentration of hydrogen ions in solution, resulting in a lower pH value.

In contrast, a weak acid does not fully ionize; instead, it only partially dissociates into hydrogen ions and its conjugate base. An example of a weak acid is acetic acid (CH₃COOH), which exists in a state of equilibrium in solution, with most of the acid remaining in its molecular form rather than dissociated. This partial ionization results in a lower concentration of hydrogen ions and subsequently a higher pH compared to a strong acid at the same concentration.

The other options do not correctly identify the distinguishing factor in terms of acid strength. While pH can indicate acidity, a strong acid will not universally have a higher pH than a weak acid; in fact, it typically has a lower pH. Conductivity could potentially suggest the strength of an acid