Answer:
10 m
Step-by-step explanation:
The mole fraction of FeCl₃ of 0.15, that is, per mole of solution, there are 0.15 moles of FeCl₃ and 1 - 0.15 = 0.85 moles of water.
The molar mass of water is 18.02 g/mol. The mass corresponding to 0.85 moles is:
0.85 mol × 18.02 g/mol = 15 g = 0.015 kg
The molality of FeCl₃ is:
m = moles of solute / kilogram of solvent
m = 0.15 mol / 0.015 kg
m = 10 m