We did this analysis in laboratory when I was in school. Itu2019s based on the equationAgNO3 + Cl (- ion ) = AgCl + NO3(- ion). Silver nitrate is soluble in water, so you take a standard aqueous solution of AgNO3 and add it to a water solution of the chloride ion containing sample. A flocculant white precipitate forms: it is silver chloride. Filter off the AgCl, wash it with water, dry it out and weigh it. Use stoichiometry to calculate the Chloride ion content of the original sample. This is a difficult experiment to carry out, since the white silver chloride darkens in light. You have to doo all this in a dark room to prevent decomposition of AgCl into the dark colored elemental silver.