Standard solution
In analytical chemistry
Analytical chemistry
Analytical chemistry is the study of the separation, identification, and quantification of the chemical components of natural and artificial materials. Qualitative analysis gives an indication of the identity of the chemical species in the sample and quantitative analysis determines the amount of...

, a standard solution is a solution
In chemistry, a solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is dissolved in another substance, known as a solvent. The solvent does the dissolving.- Types of solutions :...

 containing a precisely known concentration
In chemistry, concentration is defined as the abundance of a constituent divided by the total volume of a mixture. Four types can be distinguished: mass concentration, molar concentration, number concentration, and volume concentration...

 of an element or a substance i.e, a known weight of solute is dissolved to make a specific volume. It is prepared using a standard substance, such as a primary standard
Primary standard
A primary standard in metrology is a standard that is accurate enough that it is not calibrated by or subordinate to other standards. Primary standards are defined via other quantities like length, mass and time. Primary standards are used to calibrate other standards referred to as working...

. Standard solutions are used to determine the concentrations of other substances, such as solutions in titration
Titration, also known as titrimetry, is a common laboratory method of quantitative chemical analysis that is used to determine the unknown concentration of an identified analyte. Because volume measurements play a key role in titration, it is also known as volumetric analysis. A reagent, called the...

s. The concentrations of standard solutions are normally expressed in units of moles
Mole (unit)
The mole is a unit of measurement used in chemistry to express amounts of a chemical substance, defined as an amount of a substance that contains as many elementary entities as there are atoms in 12 grams of pure carbon-12 , the isotope of carbon with atomic weight 12. This corresponds to a value...

 per litre (mol/L, often abbreviated to M for molarity), moles per cubic decimetre (mol/dm3), kilomoles per cubic metre (kmol/m3) or in terms related to those used in particular titrations (such as titres).

A simple standard is obtained by the dilution of a single element or a substance in a soluble solvent with which it reacts.


A solution of acid can be standardized by titrating it against a solution of alkali of known concentration. Once this has been calculated, it can in turn be used as a standard solution to find the concentration of a solution of alkali.

Standard solutions are also commonly used to determine the concentration of an analyte species
An analyte, or component , is a substance or chemical constituent that is of interest in an analytical procedure. Grammatically, it is important to note that experiments always seek to measure properties of analytes—and that analytes themselves can never be measured. For instance, one cannot...

. By comparing the absorbance of the sample solution at a specific wavelength to a series of standard solutions at differing known concentrations of the analyte species, the concentration of the sample solution can be found via Beer's Law. Any form of spectroscopy
Spectroscopy is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise any interaction with radiative...

can be used in this way so long as the analyte species has substantial absorbance in the spectra. The standard solution is a reference guide to discover the molarity of unknown species.
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