CoachA standard solution is a solution whose concentration is accurately known. A calibration scale is a series of standard solutions of the same solute, at increasing concentrations, usually made by diluting one stock solution; comparing an unknown solution with it gives an estimate of the unknown’s concentration.
Examples
Example 26.16 (A blue scale)
From a stock solution of copper sulfate at , six standards are prepared at 0.02, 0.04, 0.06, 0.08, 0.10 and , each in identical tubes filled to the same height. A solution of unknown concentration, in the same kind of tube, looks darker than the tube and paler than the one: its concentration lies between the two, about .