Question

Q. Mole fraction of urea in aqueous solution is 0.25 , the find molality of solution ⁉️



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Answer 1

go through the picture

Answer 2

The Molality Of The Solution Is 18.5 Mol/Kg

GIVEN

Mole fraction of urea = 0.25

TO FIND

The molality of the solution.

SOLUTION

we can simply solve the given problem as follows-

The mole fraction of solute is given,

The mole fraction of urea in a solution = 0.25

The mole fraction of solvent will be = 1-0.25 = 0.75

Therefore,

The moles of urea = 0.25

The moles of solvent = 0.75

Since it is an aqueous solution of urea, we will take water as a solvent.

Weight of water in solution = 0.75 × 18 = 13.5 grams

To calculate the molality of the solution, we will apply the following formula -

$molality = \frac{moles \: of \: solute}{weight \: of \: solvent \: in \: kg}$

$= \frac{0.25}{13.5 \times {10}^{ - 3} }$

=

$\frac{0.25 \times {10}^{3} }{13.5}$

$= 18.5$

Hence, the molality of the solution is 18.5 mol/kg

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