Strong acid

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Acid-base reaction theories
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Systematic naming
Electrochemistry
Acids:

Strong acids
Weak acids

A strong acid is an acid that dissociates completely in an aqueous solution, or in other terms, with a pK_a < -1.74, that of hydronium. This generally means that in aqueous solution at standard temperature and pressure, the concentration of hydronium ions is equal to the concentration of strong acid introduced to the solution. While strong acids are generally assumed to be the most corrosive, this is not always true. The carborane superacid (H(CHB₁₁Cl₁₁</sub>), which is one million times stronger than sulfuric acid, is entirely non-corrosive, whereas the weak acid hydrofluoric acid (HF) is extremely corrosive and can dissolve, among other things, glass and all metals except iridium. The equation for complete dissociation of an acid in aqueous solution is as follows:

HA(aq) → H⁺(aq) + A^-(aq)

In any other acid-water reaction, dissociation is not complete, so will be represented as an equilibrium, not a completed reaction. The typical definition of a weak acid is any acid that does not dissociate completely. The difference separating the acid dissociation constants of strong acids from all other acids is so great that this is a reasonable demarcation.

Due to the complete dissociation of strong acids in aqueous solution, the concentration of hydronium ions in the water is equal to the concentration of the acid introduced to solution: [HA] = [H⁺] = [A^-]; pH = -log[H+].

1 Some Common Strong Acids (As Ionizers)
- 1.1 Extremely Strong Acids (As Ionizers)
2 External links
3 References

[edit] Some Common Strong Acids (As Ionizers)

(Strongest to weakest)

Perchloric acid HClO₄
Hydroiodic acid HI
Hydrobromic acid HBr
Hydrochloric acid HCl
Sulfuric acid H₂SO₄ (K_a1/first dissociation only)
Nitric acid HNO₃
Hydronium ion H₃O⁺

Some chemists include chloric acid (HClO₃), bromic acid (HBrO₃), perbromic acid (HBrO₄), iodic acid (HIO₃), and periodic acid (HIO₄) as strong acids, although these are not universally accepted.