How can silver nitrate be used to measure chloride ions in a solution?

Silver nitrate (${\text{AgNO}}_3$) is a primary reagent used in chemical analysis to detect and quantify chloride ions through precipitation reactions. Because silver ions react with chloride ions to form insoluble silver chloride ($\text{AgCl}$), several methods are employed:

• Gravimetric Analysis: The chloride content is determined by weighing the white precipitate of silver chloride formed when silver nitrate is added to a sample in dilute nitric acid.1
• Precipitation Titration: A standard solution of silver nitrate is added to the sample from a burette. The end point can be marked by visual indicators, such as potassium chromate, which forms a red precipitate of silver chromate upon the first slight excess of silver ions.12
• Potentiometric Titration: This method measures voltage changes during the addition of silver nitrate, allowing for precise determination even in the presence of other halides like bromide or iodide.12
• Volhard Method: This involves adding an excess of silver nitrate to precipitate the halides and then titrating the remaining unreacted silver with a thiocyanate solution.3