The first thing to do is to convert the mass of sodium sulfate to moles. Since the given is in milligrams convert it to grams which would be 0.02824 grams. The number of moles can be calculated by dividing the converted weight with the given molar mass which is 139.04 g/mol. The number of mols in the solution is 2.03x10^-4 mols. Then divide the number of moles with 0.02355 L. The molarity of the solution is 0.00862 M.
