Aqueous Sulfate Stock Solution for Standard in Ethanol 2000 mg/l - Accurately weigh 2.95 g anhydrous sodium sulfate to the nearest tenth of a milligram and transfer it to a 1 L volumetric flask. ( Dried anhydrous sodium sulfate should be stored in a desiccator .) Add type III water to dissolve the sodium sulfate and make to volume . Calculate the concentration of sulfate in the solution in accordance with Eq2