Question

Battery acid (H2SO4) contains 13% by mass H2SO4. What is the molality of the solution?

Answer 1

Explanation:

The molarity of the solution is 4.22M. Therefore 4.22 mol of H

2

SO

4

is present in 1000cm

3

of solution.

Now M(molar mass of H

2

SO

4

)=98g(mol)

−1

W(mass of H

2

SO

4

)=4.22×98=413.56g

mass of the solution=density×volume=1.21×1000=1210g

mass of water(solvent)=1210g−413.56g=796.44g=0.79644kg

m(molality)=

mass of solvent(in kg)

n

solute

m=

0.79644kg

4.22mol

=5.298mol(kg)

−1