Question

The mass percentage of hydrochloric acid within a solution is 22.00%. Given that the density of this solution is 1.110 g/mL, find the molarity of the solution.

Answer 1

consider 100 grams of solution

now

we know that

% mass = mass of solute x 100 / mass of solution

so

22 = mass of HCl x 100 / 100

mass of HCl = 22

now

we know that

moles = mass / molar mass

so

moles of HCl = 22 / 36.46

moles of HCl = 0.6034

now

volume = mass / density

given

density of solution = 1.11 g / ml

so

volume of solution = 100 / 1.11

volume of solution = 90.09 ml

now

molarity = moles of HCl x 1000 / volume of solution (ml)

so

molarity = 0.6034 x 1000 / 90.09

molarity = 6.7

so

the molarity of the solution is 6.7 M