40 g of water was evaporated from 150 g of sodium chloride solution. Calculate the mass fraction of the new salt solution?

Sodium chloride: NaCl.
1) Let the mass of the solute sodium chloride be equal to its molar mass and equal to 36.5.
2) Find the mass fraction of sodium chloride in its solution. For this, the mass of the solute is divided by the mass of the solution and multiplied by one hundred percent: 36.5 / 150 * 100 = 24.3%.
3) Mass of solution after evaporation: 150 – 40 = 110g.
4) Find the molar mass of sodium chloride after evaporation: 36.5 / 110 * 100 = 40.15% – the answer.