Question

Nitric acid is usually available in a concentrated form of 70.3% by mass aqueous solution with a density of 1.41 g/mL. Calculate the molarity and molality of this solution.

Answer 1

70.3 % HNO3 solution means 70.3g of HNO3 disolve in 100g of solution

mass of solvent = 100-70.3 = 29.7g of H2O

volume of solution = mass/density   = 100/1.41   = 70.92ml

molarity = W*1000/G.M.Wt*volume of solution in ml

               = 70.3*1000/60*70.92   = 16.52M

molality = W*1000/G.M.Wt*weight of solvent in g

             = 70.3*1000/60*29.7   = 39.45m