What mass of sodium thiosulfate pentahydrate crystals, Na2S2O3.5H2Ois needed to prepare 500 ml of .1 M Na2S2O3 titrant solution?
If 12.354 g of sodium thiosulfate penthahydrate is actually used tomake the titrnt solution (500 mL), what is the actual molarity of the sodium thiosulfate solution?