Answer to Question #172753 in General Chemistry for Kristine

Question

the molarity of 37.5 % (m/m) HCl

Answer 1

The density is 1.19 g/mL. One mL of the solution has a mass of 1.19 gms. Therefore 1000 mL of the solution has a mass of 1190 grams.

Now that we know the mass of the solution we can determine the mass of the HCl in a liter. In 1190 gms of solution, 37.5 % is HCl. 1190 x 0.375 = 446.25. So, we have 446.25 gms HCl in a liter of solution. The molecular weight of HCl is 36.5. Therefore, we have 446.25 / 36.5 = 12.23 moles HCl in each liter of the concentrated acid. Hence the molarity of HCl is 12.23.