titration
/ ty-TRAY-shun /
Imagine slowly dribbling lemon juice into a pot of soup, tasting after every drop, until it is exactly tart enough — then noting how much juice you used. Titration is that idea turned into precise chemistry: you add a solution of known strength, little by little, to a sample until a reaction is just complete, and you read off the volume.
Formally, titration measures how much of one solution (the titrant) is needed to react completely with a measured amount of the substance you are analysing. Because the titrant's concentration is known and the reaction follows a fixed recipe (its stoichiometry), the volume added tells you exactly how much of the unknown was present.
Titration matters because it is cheap, fast, and remarkably accurate when done with care, needing only glassware and a way to spot the finishing point. Its honest limit is that you must know the reaction cleanly happens in one well-defined way — side reactions or a fuzzy finishing point quietly spoil the result.
To find the acid content of vinegar, a chemist runs sodium hydroxide of known concentration from a burette into a measured sample of vinegar until the acid is exactly neutralised, then calculates the acetic acid from the volume used.
Volume of known titrant in → amount of unknown out.
Titration measures a volume that you convert to an amount; it does not directly weigh anything. It belongs to wet chemistry rather than instrumental analysis, though instruments can detect the finishing point for you.