Direct and back titration calculations

Start with a balanced equation. Calculate known moles using n= cV, with litres, then apply the reaction mole ratio. Divide unknown moles by its aliquot volume. After finding a diluted concentration, multiply by the dilution factor to recover the original concentration. Retain guard digits until the final rounding.

In back titration, subtract unused excess reagent from the initial reagent amount. Relate the amount consumed to the sample using its balanced equation. Assume complete sample reaction and no interfering reagent-consuming substances unless stated otherwise. Overshooting a direct end-point records too much titrant and usually overestimates analyte amount. Equal-mole c1V1=c2V2 applies directly only to 1:1 reactions.

Watch out: That form applies only when the reacting substances have a 1:1 mole ratio; other equations require their coefficients.