Determine the mass of water that must be added to 50 g of sulfuric acid to obtain a solution

Determine the mass of water that must be added to 50 g of sulfuric acid to obtain a solution with a mass fraction of the substance of 20%

The concentration of the in-islands in the solution of C in the islands (%) = (m in-va / m solution) * 100%.
Hence, m solution = (m in-va / C (%)) * 100%, in our case: 50 g: (20%: 100%) = 50 g * 5 = 250 g, so you need to add water 250 – 50 = 200 g.