Answer:
4423.08 L
Explanation:
First we need to know the concentration of sodium per litre (as the density is 1 g/L, 1 g of water is the same that 1 mL of water) of softened water by dividing the percentage in 100:
[tex]5.2x10^{-4}g/L[/tex]
With the value of concentration, we just need to to divide the recommended value of the FDA, that is 2300 milligrams per day, into the concentration that we have, therefore:
[tex]2300mg=2.3g\\\\\frac{2.3g}{5.2x10^{-4}g/L} =4423.08 L[/tex]