An aqueous solution containing 12.0% MgCl₂ by mass has a density of 1.105 g/mL. What is the mol fraction of water in this solution? A) 0.975 B) 0.880 C) 0.868 D) 0.133 E) 0.952

Question

Quizplus · Accepted Answer

To find the mole fraction of water, calculate the moles of MgCl2 and water in 100 g of solution. 12 g of MgCl2 (molar mass = 95.21 g/mol) gives 0.126 moles. The remaining 88 g is water (molar mass = 18.02 g/mol), giving 4.883 moles. The mole fraction of water is 4.883 / (4.883 + 0.126) = 0.975.

An Aqueous Solution Containing 12