argentometric titration
/ ar-jen-toh-MET-rik ty-TRAY-shun /
Think of silver as a magnet that pulls certain ions out of water and turns them into solid crumbs. An argentometric titration is any titration built on that magnet: you drip in a silver solution and use it to count how much of those ions were dissolved.
Formally, it is a precipitation titration that uses a silver-ion solution (usually silver nitrate) as the titrant. The silver reacts with halides such as chloride, bromide, and iodide — and with a few other ions — to form insoluble silver salts, and the volume of silver used measures the ion's amount.
It matters because it is the dominant family of precipitation titrations, covering chloride in everything from drinking water to cheese to blood serum. The three classic recipes within it — Mohr, Volhard, and Fajans — differ only in how they detect the end point; the silver chemistry underneath is the same.
A dairy lab checking the salt level in butter dissolves a sample and titrates it with standard silver nitrate; the silver precipitates the chloride, and the volume used converts directly to a salt percentage.
Silver nitrate is the shared titrant of all argentometric methods.
The name comes from 'argentum', Latin for silver — the same root as the chemical symbol Ag. Silver salts and solutions stain skin and surfaces black on exposure to light, so they are handled with care.