A commercial grade aqueous HCl solution is 37.0% (by mass) HCl and has a density of 1.18 g/mL. What is the molality of the HCl solution?

Molality is 16.1 m

Explanation:

37 % by mass indicates that 37 g of HCl, our solute, is contained in 100 g of solution. Let's determine the mass of solvent.

Mass of solution = Mass of solute + Mass of solvent

100 g = 37 g + Mass of solvent

Mass of solvent is 63 g

Let's convert the mass to kg → 63 g . 1kg / 1000 g = 0.063kg  for molality

Let's convert the mass of solute to moles → 37 g . 1 mol / 36.45 g = 1.01 moles of solute

Molality → mol/kg = 1.01 mol / 0.063 kg → 16.1 m

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