Determine the molarity of a sodium hydroxide aqueous solution that is 91% by mass. The density of the solution is 1.71 g/ml

Answer 1

MW NaOH=40.08

91/100x1.71g/mL x 1000mL/L x mol /40.08g = 38.9mol/LNaOH

Answer 2

Assume you have 1 L of solution.

1000 ml x 1.71 g/m = 1710 g of solution

91% of this mass is NaOH. So mass NaOH = 0.91 x 1710 = 1556 g NaOH

molar mass NaOH = 40 g/mole

molarity = moles/liter

1556 g x 1 mole/40 g = 38.9 moles/L = 38.9 M