To what volume do you need to dilute 50 cm³ of a 35% sodium hydroxide solution (p = 1.38 g / cm³)

To what volume do you need to dilute 50 cm³ of a 35% sodium hydroxide solution (p = 1.38 g / cm³) to obtain a 12% solution (p = 1.13 g / cm³)?

Knowing the volume and density of the solution, we calculate the mass of a 35% sodium hydroxide solution.

m (NaOH (35% solution)) = p * V = 1.38 * 50 = 69 g.

Let’s calculate the mass of sodium hydroxide contained in the solution.

m (NaOH) = 0.35 * 69 = 24.15 g.

Let’s calculate the mass of a 12% NaOH solution.

24.15 – 12%

x – 100%

x is the mass of a 12% solution.

x = 201.25 g

Let’s calculate the volume of a 12% NaOH solution.

V (NaOH) = m / p = 201.25 / 1.13 = 178.1 cm3

The volume of the initial solution is 50 cm3. Let’s calculate the volume of water that needs to be added to get a 12% solution.

V (added water) = 178.1 – 50 = 128.1 cm3