The best electrolyte solution to prepare for electrolysis of water is a 1 molar sodium sulfate solution. Sodium sulfate solutions are neutral, and the ions will not be oxidized or reduced by a low-voltage power source. Sodium chloride and hydrochloric acid solutions should be avoided because chlorine gas may be produced at the anode. To prepare 500 mL of a 1 molar sodium sulfate solution, dissolve 161 grams of sodium sulfate, decahydrate (Na2SO4.10H2O) in 400 mL of distilled or deionized water. Once dissolved, dilute the solution to a final volume of 500 mL with distilled or deionized water.