Answer:
44.2 mmHg
Explanation:
We have to apply the colligative property of lowering vapor pressure:
P° - P' = P° . Xm
where P' refers to vapor pressure of solution
P° refers to vapor pressure of pure solvent
Xm is the mole fraction of solute
Let's determine the mole fraction (moles of solute / Total moles)
Total moles = Moles of solute + Moles of solvent
Moles of solute → 15 g . 1 mol/18g = 0.833 moles
Moles of solvent → 100 g . 1mol / 46 g = 2.174 moles
Total moles = 0.833 + 2.174 = 3.007
Xm = 0.833 / 3.007 = 0.277
We replace data in the formula: 61.2 mmHg - P' = 61.2 mmHg . 0.277
P' = - (61.2 mmHg . 0.277 - 61.2 mmHg) → 44.2 mmHg
