Acid–Base Titration Concentration

\[n_aC_aV_a=n_bC_bV_b\]

Variables

Caacid concentration (mol/L)

Vaacid volume (L)

Cbbase concentration (mol/L)

Vbbase volume at equivalence (L)

naacid stoichiometric coefficient

nbbase stoichiometric coefficient

Description

What is this formula?

This formula calculates the concentration of an acid or base using titration data and the balanced chemical reaction. It extends the simple equivalence relation by including stoichiometric coefficients.

When to use it

Use this formula when the acid and base do not react in a 1:1 molar ratio or when accurate stoichiometric calculations are required.

Example

Sulfuric acid is titrated with sodium hydroxide.

Balanced reaction:

H2SO4 + 2NaOH → Na2SO4 + 2H2O

Data:

Va = 25.0 mL

Cb = 0.100 mol/L

Vb = 30.0 mL

na = 1

nb = 2

Formula:

naCaVa = nbCbVb

Substitution:

1 × Ca × 25.0 = 2 × 0.100 × 30.0

Result:

Ca = 0.240 mol/L

The sulfuric acid concentration is 0.240 mol/L.

Applications

- Acid-base titrations

- Quality control laboratories

- Pharmaceutical analysis

- Environmental chemistry

- Water treatment analysis

Note

This equation is valid at the equivalence point and requires the balanced chemical equation to determine the correct stoichiometric coefficients. For 1:1 reactions, it reduces to the simpler relation CaVa = CbVb.