Strong Acids

These are the strong acids. What makes them 'strong' is that completely dissociate into their ions (H⁺ and an anion) when they are mixed with water. Any other acid is a weak acid. There are only six strong acids, so you might want to commit the list of strong acids to memory.

HCl - hydrochloric acid

HNO₃ - nitric acid

H₂SO₄ - sulfuric acid

HBr - hydrobromic acid

HI - hydroiodic acid (also known as hydriodic acid)

HClO₄ - perchloric acid

As the strong acids become more concentrated, they may be unable to fully dissociate. The rule of thumb is that a strong acid is 100% dissociated in solutions of 1.0 M or less.