Question

Determine the molarity and molality of an aqueous concentrated hydrochloric acid solution that is 33% by mass acid with a density = 1.33 g/mL

Answer 1

formula to use

C(in molarity)= 10x(%m/m)xd/MM=10*37*1.11/37=11.1 M

In which
%m/m =37
d=1.11
MM= 37 g/mol ( molar mass)


Explanation:

37% means there are 37g of HCl in 100 g solution.

37g HCl----------------------------100g solution

A- From the 37 g calculate the number of moles
B- From the 100g of solution and density calculate the V

A- n=m/MM, n=37/37=1 mol
B- d=m/V, V=m/d, V=100/1.11 =90 ml

Now you can calculate the concentration of the solution, C=n/V

C=1/0.090= 11.1 M