What to do if a primary standard is hydrated?

If a primary standard is hydrated, it is important to first determine its water content accurately, as this can affect the standard's mass and concentration. The standard may need to be dried to a constant weight in a controlled environment, such as an oven, to remove the water of hydration. After drying, reweigh the substance to ensure accurate measurements. Finally, calculate the concentration of the solution based on the anhydrous weight to ensure precise results in subsequent experiments.