QJEEM19Chbbe7: JEE Main 2019 Chemistry - Class 11 JEEM19Chbbe7 Solution: The mole fraction of a solvent in aqueous solution of a solute…

Question

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The mole fraction of a solvent in aqueous solution of a solute is 0.8. The molality (in mol kg^–1 ) of the aqueous solution is :

Accepted Answer

We know,

molality(m) =

\frac{x_{s o l u t e}}{x_{s o l v e n t}} \times \frac{1000}{m o l a r w e i g h t o f s o l v e n t}

Here solvent is H₂O

x_solvent = 0.8

∴

x_solute = 0.2

∴

Molality =

\frac{0.2}{0.8} \times \frac{1000}{18}

= 13.88

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