In typical general chemistry, there are 7 strong acids that are commonly taught.

Quick Scoop

Most textbooks and courses define “strong acids” as those that completely dissociate in water , and under that definition you usually learn a standard set of seven.

These 7 strong acids are:

  • Hydrochloric acid, HCl
  • Hydrobromic acid, HBr
  • Hydroiodic acid, HI
  • Nitric acid, HNO₃
  • Sulfuric acid (first proton), H₂SO₄
  • Chloric acid, HClO₃
  • Perchloric acid, HClO₄

Some resources or teachers emphasize only 6 “must‑know” strong acids (usually HCl, HBr, HI, HNO₃, H₂SO₄, HClO₄), but the full standard list in many references is 7, which is what most exam-prep and reference sites state explicitly.