# To what volume should water be added to 250 ml of a 30% potassium nitrate solution

**To what volume should water be added to 250 ml of a 30% potassium nitrate solution (solution density 1.13 g / ml) to prepare a 10% solution (density 1.044 g / ml)?**

Knowing the volume and density of the solution, we calculate the mass of a 30% potassium nitrate solution.

m (KNO3 (30% solution)) = p * V = 1.13 * 250 = 282.5 g.

Let’s calculate the mass of potassium nitrate contained in the solution.

m (KNO3) = 0.3 * 282.5 = 84.75 g.

Let’s calculate the mass of a 10% KNO3 solution.

84.75 – 10%

x – 100%

x is the mass of a 10% solution.

x = 847.5 g

Let’s calculate the volume of a 10% KNO3 solution.

V (KNO3) = m / p = 847.5 / 1.044 = 811.8 ml

The volume of the initial solution is 250 ml. Let’s calculate the volume of water that needs to be added to get a 10% solution.

V (added water) = 811.8 – 250 = 561.8 ml