Calculate molality of sulphuric acid solution …

If the mole fraction of water is 0.85, the mole fraction of sulfuric acid is 0.15.
So, we can express the concentration as
{tex}\frac { 0.15 \mathrm { mol } \text { sulfuric acid } } { 0.85 \text { mol water } }{/tex}
Convert moles of water to kilograms of water
Mass of water = {tex}0.85 \mathrm { mol } \mathrm { H } _ { 2 } \mathrm { O } \times \frac { 18.02 \mathrm { g } \mathrm { H } _ { 2 } \mathrm { O } } { 1 \mathrm { mol } \mathrm { H } _ { 2 } \mathrm { O } } \times \frac { 1 \mathrm { kg } \mathrm { H } _ { 2 } \mathrm { O } } { 1000 \mathrm { g } \mathrm { H } _ { 2 } \mathrm { O } }{/tex}
=0.0153 kg H₂O
Calculate the molal concentration of the water
m = {tex}\frac { 0.15 \mathrm { mol } \text { sulphuric acid } } { 0.0153 \mathrm { kg } \text { water } }{/tex}= 9.8 mol/kg