Calculate the volume of water necessary to obtain a solution of 150 grams of NaCl 19% by Weight.

Answer 1

The definition of 19% by weight means 19 grams of NaCl per 100 grams of solution.

If we assume the density of solution to be the same as water, i.e. 1 g / ml, then ...

19% by weight = 19 g NaCl / 100 g soln

19 g / 100 ml = 150 g / x ml

x = 789 g of solution

So, you'd need 789 mls of water assuming the NaCl doesn't add to the volume and that the density of the solution is 1 g / ml. Neither of these are probably valid assumptions, but without additional information, this is the best we can do.