A word used to describe a phase, which can be a liquid or a solid, containing a substance dissolved in a large volume/amount of a second substance. This second substance is commonly called the solvent.
Buffer solution
Primary standard solution
Standard solution
A solution for which the pH value is relatively stable with respect to the addition of dilute acid or dilute base.
This is a solution whose composition is known to a high degree of accuracy, which is very stable and which can be successively diluted according to the needs of a particular analytical procedure.
A solution of accurately known composition used to calibrate measuring apparatus or to validate (check) a method of analysis.
For example, in colorimetry a standard solution is a solution of known concentration of the coloured product.
It is important that standard solutions do not readily decompose. Standard solutions should be stable nevertheless they should not be stored indefinitely.