Fluoroantimonic acid (HSbF6) is the strongest acid, sometimes known as a superacid.
It’s formed by mixing hydrogen fluoride with antimony pentafluoride. Fluoroantimonic acid is much stronger than sulfuric acid, which is already a strong acid, and it’s recognized for its ability to protonate compounds that traditional strong acids cannot.
However, it’s important to note that the concept of “strongest acid” can vary based on context and criteria, and the strength of an acid can depend on factors such as the solvent, temperature, and the specific reactions being considered.