In a certain mass of water, 0.25 mol of potassium hydroxide was dissolved and a solution with a mass

In a certain mass of water, 0.25 mol of potassium hydroxide was dissolved and a solution with a mass fraction of salt of 28% was obtained. Determine the mass of water used to prepare the solution. Give your answer to the nearest 0.1 (g)

Find the mass of potassium hydroxide:

m (KOH) = v (KOH) * M (KOH) = 0.25 * 56 = 14 (g).

Find the mass of this potassium hydroxide solution:

mr.-ra (KOH) = m (KOH) * 100 / w (KOH) = 14 * 100/28 = 50 (g).

Let’s find the mass of water used to prepare this solution:

m (H2O) = mr.-pa (KOH) – m (KOH) = 50 – 14 = 36.0 (g).