Titration is a versatile analytical procedure that can be used for a wide variety of chemical analyses. For example, when your town’s water supply is tested for purity, or pond water is tested for dissolved oxygen and contaminants, chances are a titration is carried out. Some tests essential for a medical diagnosis require a titration of various body fluids. A titration makes use of a known reaction between two chemicals. A solution of unknown concentration is reacted with a precisely measured amount of another chemical. An appropriate indicator must be used to determine when chemically equivalent amounts of each chemical are combined, that is, when no excess of either.