Calculate the mole fraction of ethanol in 0.5 m aqueous solution of ethanol.

Dear Student,

Please find below the solution to the asked query.

Molality of solution = 0.5
You know, 
Molality = $\frac{number of moles of solute}{mass of solvent in kg}$
This means 0.5 moles of ethanol is dissolved in 1 kg of water.

So, number of moles of ethanol = 0.5
Number of moles of water = $\frac{mass}{molar mass}=\frac{1000 g}{18 g/mol}=55.55$
So, mole fraction of ethanol = $\frac{number of moles of ethanol}{number of moles of ethanol + number of moles of water}=\frac{0.5}{0.5 + 55.55} = 0.09$

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Akanksha Jain