Primary standard

Primary standards are defined via other quantities like length, mass and time.

Here, a primary standard is typically a reagent which can be weighed easily, and which is so pure that its weight is truly representative of the number of moles of substance contained.

Features of a primary standard include: (The last two are not as essential as the first four.)

Some examples of primary standards for titration of solutions, based on their high purity, are provided:[4] Such standards are often used to make standard solutions.

These primary standards are used in titration and are essential for determining unknown concentrations[1] or preparing working standards.