Question

What is the molality of 1 L solution of H2SO4 which is 46 percent wt/vol ?

Answer 1

( Density of solution is also required in this question, the solution is given considering d=1.4 gm/cm3 )

-46% (w/v) H2SO4 = 46 g of H2SO4 in 100 mL of solution

-thus in 1000 mL solution of H2SO4, amount of H2SO4 is 460 gm

- no of moles in 460 gm = 460 ÷98 = 4.69 mole

-Mass of 1L solution = volume × density = 1000× 1.4 = 1400 g

-Mass of solvent in 1L Solution = 1400-460 =940 g = 0.94 kg

-Hence, Molality (m) = 4.69÷0.94 = 4.989 (m)

Answer 2

Answer:

5 molal (approx)

Explanation:

46% wt/vol means in 100ml of solution 46 g solute is present

(given density of solution is 1.4 gm/cc)

total mass of solution = density× vol

=1.4÷100 =140gm

so mass of the solvent = 140-46 =94gm =0.094kg

so molality = no. of moles of solute / mass of solvent(kg)

= (46/98)÷ 0.094

=4.99 m

~5 molal