What is normality?
Normality (N) is a measure of concentration based on equivalents per liter. One equivalent is the amount of a substance that reacts with or supplies one mole of H⁺ (for acids) or one mole of e⁻ (for redox).
N = M × n
Where M = molarity and n = number of equivalents per mole (e.g., H₂SO₄ = 2, HCl = 1, H₃PO₄ = 3).
Common equivalents
- HCl: n = 1 (one H⁺)
- H₂SO₄: n = 2 (two H⁺)
- H₃PO₄: n = 3 (three H⁺)
- NaOH: n = 1 (one OH⁻)
- Ca(OH)₂: n = 2 (two OH⁻)
- K₂Cr₂O₇ (oxidizing): n = 6