Answer:
Standard solution
Explanation:
In chemistry, standard solutions are solutions that contain a very well known concentration of a substance such as solutes. In other words, standard solutions contain solute concentrations that are accurately (without errors) known. They are prepared by dissolving a known mass of solute in a known volume of solvent.
Standard solutions are majorly used to determine the concentration of another solution, whose concentration is unknown. Standard solutions contain a primary standard, which possess characteristics such as high solubility, high purity etc.