ChemistryStepByStep

Titration Calculator

Enter three of acid/base molarity and volume at the equivalence point to solve for the fourth.

This is a lab chemistry concentration calculation, not medical or dosing advice.

1 for HCl; 2 for H2SO4

1 for NaOH; 2 for Ca(OH)2

Acid molarity, M_acid (mol/L)
0.1200
at the equivalence point

M_acid × V_acid × n_acid = M_base × V_base × n_base, so Acid molarity = 0.1200.

The Titration Equation

At the equivalence point, moles of acid H+ exactly equal moles of base OH-. Since moles is molarity times volume, and some acids/bases contribute more than one H+ or OH- per molecule, the full relationship is M_acid × V_acid × n_acid = M_base × V_base × n_base, where n is the number of acidic or basic equivalents per formula unit.

Most commonly this solves for an unknown solution's molarity, using a known-concentration titrant and the volume it took to reach the equivalence point.

Worked example

25 mL of an unknown HCl solution is titrated with 0.1 M NaOH, reaching the equivalence point at 32.5 mL of NaOH added. Both are 1:1 acids/bases (n = 1). Find the HCl concentration.

M_acid = (M_base × V_base × n_base) / (V_acid × n_acid) = (0.1 × 32.5 × 1) / (25 × 1) = 0.1300 M.

Common mistake

Forgetting the n factor for a polyprotic acid or base -- treating H2SO4 as n = 1 instead of 2 halves the moles of H+ it actually contributes, throwing off the whole result.

Keep going

  • A titration's result is the unknown solution's molarity; the molarity calculator is where you'd double-check that same concentration from moles and volume directly. Molarity Calculator
  • A titration finds the equivalence point where moles of acid and base match; the pH calculator finds the actual pH from a hydrogen-ion concentration at any point in that reaction. pH Calculator

Frequently Asked Questions

What is a titration?

A lab technique for finding an unknown solution's concentration by slowly adding a solution of known concentration (the titrant) until the reaction is exactly complete (the equivalence point) -- usually signaled by a color-change indicator or a pH meter reading.

What does 'equivalence point' mean here?

The point where moles of acid exactly equal moles of base, accounting for how many H+ or OH- each formula unit provides. For simple 1:1 acids and bases (HCl and NaOH), that's just Macid × Vacid = Mbase × Vbase.

What are n_acid and n_base for?

They account for acids or bases that release more than one H+ or OH- per formula unit -- sulfuric acid (H2SO4) gives 2 H+ per molecule, so n_acid = 2. Most common strong acids and bases (HCl, NaOH, HNO3) use n = 1.

Is titration only for acid-base reactions?

No -- titration is also used for redox reactions and other reaction types, but this calculator's equation (M×V×n on both sides) specifically models the acid-base case, the most common titration taught in introductory chemistry.

Is this calculator meant for real lab or medical dosing?

No. This is a lab chemistry concentration calculation for coursework and general reference -- 'concentration' here means a solution's molarity in mol/L. It is not medical, pharmaceutical, or dosing advice, and shouldn't be used to determine a real medication or supplement dose.

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