A solution of accurately known concentration, prepared using standard substances in one of several ways. A
primary standard is a substance of known high purity which may be dissolved in a known volume of solvent to give a
primary standard solution. If
stoichiometry is used to establish the strength of a
titrant, it is called a
secondary standard solution. The term
secondary standard can also be applied to a substance whose active agent contents have been found by comparison against a
primary standard. Concentrations of standard solutions may be expressed in
,
,
or in terms more closely related to those used in specific titrations (as titres).
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