Which factor determines the strongest acid based on the acidity constant (Ka)?

The strength of an acid is determined by its ability to dissociate in solution, which is quantifiably expressed by the acidity constant (Ka). A larger Ka value indicates a greater degree of ionization, meaning the acid is more effective at releasing protons (H⁺) into the solution. This results in a stronger acid.

In this scenario, the choice that states the largest Ka value with the lowest exponent represents the strongest acid, as a large Ka value implies that the acid dissociates significantly in solution, thereby contributing more hydrogen ions. A low exponent indicates that even at lower concentrations, the acid still competes effectively in terms of ionization.

Conversely, a small Ka value suggests that the acid does not ionize to a significant extent, reflecting a weaker acid, regardless of its exponent. Thus, focusing on maximizing the Ka value, particularly with a low exponent, accurately correlates to a stronger acid, making it the preferred choice for identifying the strongest acid based on the acidity constant.