Acid-Base Titration Calculator
Work through acid-base titration calculations with the mole working shown: find an unknown concentration, the volume needed for neutralization, or the original concentration after dilution. Enter the acid and base valences directly.
Side with known concentration
Side to solve
Acid
Base
e.g. 10 mL made up to 100 mL gives 10
Standard solution (known concentration)
HCl = 1, H₂SO₄ = 2, NaOH = 1, Ca(OH)₂ = 2, etc.
Try an example
Choose a pattern and enter the values and valences.
How to use
- 1
Pick a pattern
Choose unknown concentration, required volume, or titration after dilution.
- 2
Enter values and valences
Enter concentrations (mol/L), volumes (mL) and the acid/base valences (1 for HCl, 2 for H₂SO₄).
- 3
Check the working
Follow the ion amount, the neutralization equality, and the final concentration or volume, with a significant-figure note.
Features
- Three patterns: unknown concentration, required volume, titration after dilution
- Specify the acid and base valences (HCl = 1, H₂SO₄ = 2, Ca(OH)₂ = 2 and so on)
- Shows the working: ion amount, neutralization equality, then the answer
- Runs entirely in your browser; no sign-up and nothing uploaded
Use cases
Check homework
Verify titration problems with the mole working shown.
Plan an experiment
Estimate the standard-solution volume or concentration before a titration.
Vinegar and drink analysis
Recover the original sample concentration from a titration after dilution.
Details
A titration drips a solution of known concentration (the standard solution) into a solution of unknown concentration until they exactly neutralize. At the equivalence point, the amount of hydrogen ions (H⁺) the acid supplies equals the amount of hydroxide ions (OH⁻) the base supplies.
The calculation uses "valence × molarity × volume". For an acid with valence a, concentration c and volume v (L) and a base with a′, c′ and v′, the equality is a×c×v = a′×c′×v′. Volumes may be kept in mL on both sides because the units cancel, but convert to litres when checking the mole amounts.
For a titration after dilution, first find the diluted concentration from the equality, then multiply by the dilution factor (original volume to flask volume) to recover the original concentration. The stoichiometric relationship holds for weak acids and bases too, although the titration curve and indicator choice depend on their strength.
FAQ
Should I enter volumes in mL or L?
Use mL. The tool converts to litres internally for the mole amounts. In the neutralization equality the volume units cancel as long as both sides match, so mL works for the ratio too.
How do I decide the valence?
For an acid it is the number of H⁺ ions one molecule can release; for a base it is the number of OH⁻ ions. HCl, HNO₃ and acetic acid are 1; H₂SO₄ is 2; NaOH and KOH are 1; Ca(OH)₂ and Ba(OH)₂ are 2.
Does the formula work for weak acids and bases?
Yes. The stoichiometric relationship does not depend on the degree of ionization. However, the pH at the equivalence point differs from the strong-strong case, so choose the indicator carefully.
How should I handle significant figures?
The display uses three significant digits as a guide. Round once at the end to match the digits given in your problem (often three).
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Verified: Textbook cases (10.0 mL HCl titrated with 15.0 mL of 0.100 mol/L NaOH giving 0.150 mol/L, diprotic acid giving 0.0750 mol/L, vinegar diluted tenfold giving 0.800 mol/L, and neutralization with Ca(OH)₂ giving 25.0 mL) plus error handling are covered by browser tests