Calculator
At equivalence: CₐVₐ × acid equivalents = CᵦVᵦ × base equivalents. Use matching concentration and volume units.
Formula and assumptions
CₐVₐ × acid equivalents = CᵦVᵦ × base equivalents
At the equivalence point, acid and base reacting equivalents are equal. The equivalents fields handle acids or bases that donate or accept more than one proton per formula unit.
Assumption: At equivalence, the reacting acid and base equivalents are equal.
Variables and units
Worked example
25.0 mL of 0.100 M monoprotic acid requires 25.0 mL of 0.100 M monobasic base at equivalence.
Worked example and mole ratios
25.0 mL of hydrochloric acid needs 20.0 mL of 0.100 M sodium hydroxide to reach the end point. Moles of NaOH = 0.100 × 0.0200 = 0.00200 mol; HCl reacts 1 : 1, so the acid concentration is 0.00200 / 0.0250 = 0.0800 M. With sulfuric acid, H₂SO₄ + 2NaOH, the ratio is 1 : 2 and the same titre would mean 0.0400 M acid. Convert millilitres to litres before multiplying.
Important limits
It is not a titration curve, pH-at-equivalence or indicator-selection calculator.
Reference and related tools
OpenStax: Acid-base titrations. Return to Chemistry Calculators for the other tools in this group.