Question

A 14.2% by mass HCl solution has a density of 1.1684 g/mL. What is the concentration of this solution in molarity?

Answer 1

Answer:

[HCl] = 4.54 M

Explanation:

14.2 % by mass is 14.2 g in 100 g of solution.

Let's calculate the moles of our solute, HCl

14.2 g / 36.45 g/mol = 0.389 mol

Molarity is mol/L (moles of solute in 1L of solution)

Let's determine the volume of solution with density

Solution density = Solution mass / Solution volume

Solution volume = Solution mass / Solution density

Solution volume = 100 g / 1.1684 g/mL → 85.6 mL

For molarity, we need the volume in L. Let's make the unit change.

85.6 mL . 1 L/1000mL = 0.0856L

Molarity is 0.389 mol / 0.0856L → 4.54 M