# Normality

The normality (

*N*) of a solution is the number of equivalents of solute per liter of solution. The*equivalent*is usually defined in terms of a chemical reaction. For acid-base reactions, an equivalent is the amount of substance that will react or form 1 mole of hydrogen (H^{+}) or hydroxide (OH^{â€“}) ions. For redox (oxidation-reduction) reactions, an equivalent is the amount of substance that will react or form 1 mole of electrons.

Normality is a multiple of molarity. The following equation relates normality and molarity.

*N = n M*

For acids, the number of H

For example, 1
For bases, the number of OH

For example, a 2

^{+}available from a formula unit of the acid gives the number of equivalents (*n*).For example, 1

*M*H_{2}SO_{4}solution is a 2*N*solution, because each molecule of H_{2}SO_{4}can give two H^{+}.^{â€“}available from a formula unit of the base gives the number of equivalents.For example, a 2

*M*Ca(OH)_{2}solution is a 4*N*solution.