Concentrated hydrochloric acid has a density of 1.15g cm^-3 and contains 30.0% by mass hydrogen chloride. How do you determine the concentration of the hydrochloric acid?

Question

anonymous · Answer

A liter of solution would have 1150 g of hydochloric acid because of the given density, therefore it would contain 30% of that as HCl, that is 345g HCl. HCl has a molar mass of 36.461g/mol, so to calculate the number of moles in the solution, you do (346g) / (36.461g/mol) =  9.49 mol of HCl  That was for one liter of solution so the concentration is 9.49 molar (or moles per liter).