Which of the following is not considered a strong Arrhenius acid?

HF, or hydrofluoric acid, is not considered a strong Arrhenius acid due to its limited ionization in water. While it can release protons (H⁺) when dissolved, the extent of this ionization is much less compared to other strong acids like HClO4 (perchloric acid), H2SO4 (sulfuric acid), and HNO3 (nitric acid). Strong Arrhenius acids are characterized by their ability to ionize completely in solution, producing a high concentration of hydrogen ions. In the case of HF, the presence of strong hydrogen-fluorine bonding results in a much weaker acid, which does not fully dissociate in solution. Therefore, HF is classified as a weak acid, distinguishing it from the others listed, which are strong acids and exhibit nearly complete ionization when dissolved in water.