titrant

A titrant is a reagent of known concentration and fixed composition used in titration to determine the amount of analyte present in a sample. It is typically a standard solution delivered from a burette and reacts with the analyte in a well-defined stoichiometric relationship.

Key requirements for a titrant include accurate knowledge of its concentration, high purity, chemical stability under the titration conditions, and compatibility with the reaction medium. The titrant is often a primary standard or a solution standardized against a primary standard to ensure its true concentration is known before use.

During titration, the titrant is added gradually to the analyte until the reaction reaches completion. The end point is the apparent completion detected by an indicator or instrument, while the equivalence point is the theoretical point where stoichiometric amounts have reacted. Accurate determination of the titrant’s concentration is essential for calculating the amount of analyte using stoichiometry.

Common titrants include sodium hydroxide for acid–base titrations, hydrochloric acid or other strong acids for base titrations, potassium permanganate or potassium dichromate for redox titrations, EDTA for metal-ion complexation titrations, and silver nitrate for certain precipitation titrations. The choice of titrant depends on the nature of the analyte, the desired reaction pathway, and the method of endpoint detection (indicator-based or instrumental).