Question

How much water should be added to 15g of NaCl to obtain 15℅ of salt solution ?

Answer 1

The mass by mass percentage of a solution is given by the following relation

where mass of solution = mass of solute + mass of solution

Here, mass of the solute (i.e. salt) = 15 g and the required concentration of the solution is 15 %.

Let the mass of water be a grams.

So,

15 = [15 / (15 + a)] X 100

Solving for a, we get

a = (100 - 15)g = 85 g