In argentometric precipitation titrations, visual detection of the endpoint is possible by the Mohr, Volhard, and Fajans methods. In the Mohr method for the determination of chloride, a soluble chromate indicator is employed. The first excess of silver ions combines with the chromate ions to form a red precipitate, indicating the endpoint. In the Volhard method, a known excess of AgNO3 is added to the chloride solution, and the resulting AgCl is removed by filtration. The excess of silver ions in the filtrate is back-titrated against standard thiocyanate, with Fe3+ added as an indicator. A soluble red complex marks the endpoint of the titration. Fajans method is based on anionic adsorption indicators that have different colors when adsorbed and in solution. Before the equivalence point, excess chloride ions are adsorbed on the precipitate, and the indicator remains in the solution. However, beyond the equivalence point, the precipitate surface is positively charged. Now, the indicator is adsorbed, resulting in a color change that marks the endpoint.