Precipitation Titration and Complex Formation Titration:

A reaction might be made the basis of a conductometric precipitation titration given the reaction product is sparingly soluble or is a stable complex. A solubility of the precipitate (or the dissociation of the complex) should be less than 5 percent. The further of ethanol is sometimes recommended to decrease the solubility within the precipitations. An experimental curve is provided in Figure (ammonium sulphate in aqueous-ethanol solution with barium acetate). The conductance at the equivalence point should be given through AB and not the observed AC if the solubility of the precipitate were negligibly small. The addition of excess of the reagent depresses the solubility of the precipitate and, if the solubility is not too huge, the position of the point B could be determined through continuing the straight portion of the two arms of the curve until they intersect.

Figure: Precipitation titration. Conductometric titration of (NH₄)₂ SO₄ vs. barium acetate