Back Titration
A technique in which excess reagent is added and the unreacted portion titrated to find how much reacted with the analyte.
Formula / equation
n_reacted = n_added − n_remaining
Unit
mol
In depth
Back titration is used when the direct reaction is too slow, when the analyte is insoluble, or when no suitable end point exists for the direct approach. Two accurately known quantities are involved, so errors from both must be considered.
Examples in the real world
Determining calcium carbonate in an antacid by dissolving it in excess acid and titrating the remainder.