Question

prepare the 38g/l solution of na2s2o3.5h2o in the 250ml volumetric flask

calculation the actual mass and concentration for the na2s2o3.5h2o solution

the mass of solution 9.3 g

Answer 1

Solution :-

38.9 g/ L

250 ml = 0.250 L

So the mass of the Na2S2O3.5H2O = 38.9 g * 0.250 L / 1 L = 9.725 g

Now lets calculate the moles of the 9.725 g Na2S2O3.5H2O

Moles = 9.725 g / 248.184 g per mol

             = 0.0392 mol

Molarity = moles / volume in liter

                 = 0.0392 mol / 0.250 L

                = 0.157 M Na2S2O3.5H2O

So the concetration of the solution of 38 g/L is 0.157 M Na2S2O3.5H2O