Normality

In chemistry, normality (N) is a term used to indicate chemical concentrations that is typically only used for acid-base reactions. A 1 normal (1 N) solution of any acid can neutralize an equal volume of any 1 N base soltuion. A one liter volume of a 1 N acid solution will neutral 1 mole, or 6.23 * 10^23, hydroxide ions. Normality is always greater than or equal to the related concentration unit molarity, such that

$\mathbf {N} =\mathbf {n} \times \mathbf {M}$

where n is an integer greater than or equal to 1.

For a monoprotic acid like hydrochloric acid, HCl, which can provide only 1 mole of protons ( hydronium ions, H₃O⁺) per mole of acid, 1M = 1N. A diprotic acid like sulfuric acid, H₂SO₄, provides two moles of protons per mole of acid and thus a 1 molar solution of sulfuric acid is a 2 normal solution.