Question

250 cm3 of sulphuric acid solution contain 24.5 g of H2SO4. Of the density of the solution is 1.98g cm-3, determine (i) molarity and (ii) molality.

Answer 1

vol of soln=250 cc=250 ml

wt of H2SO4 =24.5 g

density of soln=1.98 g/cc

as, d=m/v

1.98=x/250

x=total mass of soln

x=495 g

×=mass of water+mass of H2SO4

mass of water=x - mass of H2SO4

mass of water=495-24.5=470.5g

moles of water =470.5/18=26.13

M=moles of solute/vol of soln

moles of solute=24.5/98=.25

M=.25/250ml=.25/.25L=1 M

also

m=moles of solte/wt of solvent in kg

=.25/470.5g

=.25/.4705 kg

=.531 m....approx

Hope it is correct...do let me know