A concentrated hydrochloric acid solution is 37.2% HCl by mass and has a density of 1.19 g/mL at 25°C.What is the molarity of HCl?
A) 12.1 M
B) 0.0434 M
C) 8.57 M
D) 11.7 M
E) 0.0857 M

Question

Quizplus · Accepted Answer

To find the molarity of HCl, we first calculate the mass of HCl in 1 liter of solution. Since the density is 1.19 g/mL, 1 liter (1000 mL) of solution has a mass of 1190 g. With 37.2% of this mass being HCl, the mass of HCl is 0.372 * 1190 g = 442.68 g. The molar mass of HCl is approximately 36.46 g/mol, so the number of moles of HCl in 1 liter of solution is 442.68 g / 36.46 g/mol = 12.14 mol. Therefore, the molarity, which is moles of solute per liter of solution, is approximately 12.1 M.

A Concentrated Hydrochloric Acid Solution Is 37